Attitude toward immunization and risk perception of measles, rubella, mumps, varicella, and pertussis in health care workers working in 6 hospitals of Florence, Italy 2011

Abstract

Background: Health care workers (HCWs) are at risk of infection and transmission of vaccine-preventable infectious diseases. In recent years cases of measles or varicella in health care workers were observed with increasing frequency. The aim of our study was to investigate attitude toward immunization and risk perception of measles, rubella, mumps, varicella, and pertussis in HCWs working in 6 hospitals of Florence (Italy).

Methods: A cross-sectional survey among the physicians, nurses, midwives, and nursing assistants working in selected departments was performed trough a self-administered, anonymous questionnaire. Overall, 600 questionnaires were sent and 436 HCWs’ completed forms were included into the study (Participation rate: 72.7%). Data were analyzed with STATA 11.0® and odds ratio (OR) were calculated in a multivariate analysis.

Results: Among all respondents 74.9% were females. The average age was nearly 43-years-old (42.9 – SD 8.95). The majority of participants (58.6%) were nurses, 21.3% physicians, 12.9% nursing assistants, and 7.2% were midwives. Among those HCWs reporting no history of disease, 52.8% (95% CI: 42.0–63.3%) declared to have been immunized for measles, 46.9% for rubella (95% CI: 39.0–54.9%), 21.6% for mumps (95% CI: 15.1–29.4%), 14.9% for varicella (95% CI: 7.4–25.7%), and 14.5% for pertussis (95% CI: 10.0–20.0%). When considering potentially susceptible HCWs (without history of disease or vaccination and without serological confirmation), less than a half of them feel at risk for the concerned diseases and only less than 30% would undergo immunization. One of the main reasons of the relatively low coverage was indeed lack of active offer of vaccines.

Conclusion: Attitudes toward immunization observed in this study are generally positive for preventing some infectious diseases (i.e., measles and rubella), but relatively poor for others (i.e., varicella). More information should be made available to HCWs on the benefits of vaccination and efforts to encourage vaccination uptake should be performed. Educational program on the risk of being infected working in a hospital should be implemented in order to increase the risk perception toward infectious diseases among HCWs.

Keywords:

• vaccine preventable diseases
• measles
• rubella
• mumps
• varicella
• pertussis
• health care workers (HCWs)
• risk perception
• HCWs immunization

Abbreviations:

• EU, European
• HCW, Health Care Worker
• SD, standard deviation
• VPD, vaccine preventable disease
• VZV, varicella zoster virus

Introduction

Health care workers (HCWs) are exposed to different infectious agents and they can represent a source of infection for susceptible patients or other colleagues.

HCWs have a higher risk of exposure to communicable diseases and therefore should be protected through vaccination in order to avoid damage to the operators themselves and to avoid transmission of infectious diseases to patients and cause outbreaks in hospital setting. The risk of nosocomial infection is related to the incidence in the general population and to the proportion of susceptible HCWs in the work setting.^1,2

Despite the regional recommendations of the National Plan for Elimination of Measles and Congenital Rubella³ (since 2003) to increase immunization coverage in children, adolescents, and high risk groups, such as HCWs or susceptible women of childbearing age, in Tuscany outbreaks of measles and rubella have occurred in the last years, including nosocomial transmission and involving HCWs.⁴ Although the absolute number of cases related to these infectious diseases has decreased since the first years of vaccination introduction, a rise in the median age of infection was observed, especially for measles and rubella cases.^5,6 This changing epidemiology is well documented in Italy and in Tuscany too, where suboptimal levels of vaccination coverage against measles and rubella were maintained for many years and pockets of susceptible people were discovered in adolescents and young adults.^7,8 Moreover, in Italy, as far as varicella is concerned, the percentage of susceptible adolescents is at least nearly twice as high as in other European countries and in the age group 20–39 y, almost 10% of individuals are susceptible to VZV.⁹ In Tuscany the universal immunization program against varicella with measles-mumps-rubella-varicella (MMRV) vaccine in toddlers aged 13–15 mo was introduced in Tuscany since July 2008, previous recommendations suggested to vaccinate susceptible adolescents and high risk groups against varicella, in order to avoid more severe cases in adulthood.¹⁰

Some studies have demonstrated the presence in Italy of a higher number of susceptible subjects and a major incidence in general population for measles, varicella, rubella, and pertussis than in the rest of Europe.^11-13 Measles, rubella, mumps, and varicella are highly contagious viral infections diseases that can cause serious complications, in particular in immunocompromised patients, newborns, and pregnant women. Occupational acquired mumps, measles, varicella, rubella, and pertussis can be associated with a prolonged morbidity in HCWs and patients.¹⁴ Numerous outbreaks of measles,^15-17 rubella,¹⁸ varicella,^19,20 pertussis,^21,22 and mumps^23,24 have been described in HCWs. In recent years cases of measles and varicella in HCWs were observed with increasing frequency and with the occurrence of severe complications, as it is expected when those viruses affected an adult.^25,26

The onset and evolution of such outbreaks is facilitated by the fact that many vaccine preventable diseases (VPDs) spread rapidly in closed settings even before the onset of symptoms. Moreover VPDs are considered childhood illnesses and therefore adults do not perceive themselves to be at risk of infection, besides some VPDs may manifest with atypical symptoms which hampers rapid diagnosis (e.g., Pertussis).²⁷

The exposure of susceptible workers to a single case can put at risk and infect both HCWs and patients.^4,20,22,28

Vaccinations of HCWs at risk constitute a major infection prevention measure. It is important to identify non-immune workers and promote vaccination campaigns to prevent nosocomial infections and their consequences.²⁹

The aim of our study was to assess the risk perception related to measles, rubella, mumps, varicella, pertussis in a sample of HCWs working in the 6 hospitals of Florence (Italy) and their attitude toward the improvement of immunization coverage among HCWs.

Results

Characteristics of the sample

All 6 public hospitals of the Local Health Unit of Florence agreed to participate. Overall, 600 questionnaires were sent and 436 HCWs’ completed forms were included into the study (participation rate: 72.7%). Among all respondents 74.9% were females (male/female ratio 0.34) (Table 1).

Table 1. Demographic characteristics of the responders (n = 436) to the survey. Local Health Unit of Florence (Italy), 2011.

Characteristics	%	(n)
Sex
Male	25.1	(109)
Female	74.9	(325)
Age group (Years)
20–29	7.6	(32)
30–39	27.7	(117)
40–49	40.0	(169)
50+	24.8	(105)
Profession
Nurse	58.6	(251)
Physician	21.3	(91)
Nursing Assistant	12.9	(55)
Midwife	7.2	(31)
Workplace
Emergency	37.5	(157)
Maternal and Child	31.3	(131)
Intensive care	19.6	(82)
Infectious disease	6.7	(28)
Operating Room	5.0	(21)
Contacts per week
1–25	26.3	(104)
26–50	27.6	(109)
>50	46.1	(182)
Length of service (years)
<5	12.3	(53)
6–10	17.4	(75)
11–20	29.7	(128)
>20	40.6	(175)
Nationality
Italian	98.6	(430)
Other	0.7	(3)
Not answered	0.7	(3)

The average age was nearly 43-y-old (42.9 – SD 8.95), ranging between 23- and 64-y-old. All interviewees had Italian nationality, except 3 professionals, coming from Romania, Germany, and Switzerland.

As far as the professional position is concerned, the majority of participants (58.6%) were nurses, 21.3% physicians, 12.9% nursing assistants, and 7.2% were midwives. As far as the workplace is concerned, 37.5% of participants work in the Emergency Department, 31.2% in maternal and child healthcare, 19.6% in the Intensive Care Unit, 6.7% in the Infectious Diseases Department, and 5.0% in the Operating Room.

When asked how many patients they came in contact with per week, 26.3% of interviewees answered less than 25, 27.6% said between 26 and 50, 46.1% answered more than 50; 41 of them (9.4%) did not answer this question. With regard to seniority (length of service), 12.3% of them had been working in healthcare for less than 5 y, 17.4% for 6–10 y, 29.7% for 11–20 y and 40.6% for more than 20 y.

History of disease and reported vaccination status against measles, mumps, rubella, varicella, and pertussis

The majority of interviewees declared they had already contracted the considered diseases: 79.1% of them reported history of measles, 68.0% of mumps, 62.8% of rubella, 84.6% of varicella, and 52.2% of pertussis (Table 2).

Table 2. Reported history of disease, reported vaccination, and subjects potentially susceptible in a sample of HCWs. Local Health Unit of Florence (Italy), 2011.

Disease	N	Reported history of diseasen (%)	Reported vaccinationn (%)	Subjects potentially susceptiblen (%)
Measles	436	345 (79.1%)	48 (11.0%)	43 (9.9%)
Mumps	435	296 (68.0%)	30 (6.9%)	109 (25.1%)
Rubella	436	274 (62.8%)	76 (17.4%)	86 (19.7%)
Varicella	436	369 (84.6%)	10 (2.3%)	57 (13.1%)
Pertussis	433	226 (52.2%)	30 (6.9%)	177 (40.9%)

Among those HCWs reporting no history of disease, reported vaccination coverage was 52.8% for measles (half of them declared they have received only one dose), 46.9% for rubella, 21.6% for mumps, 14.9% for varicella, and 14.5% for pertussis (Table 3).

Table 3. Reported vaccination coverage among HCWs with no reported history of disease. Local Health Unit of Florence (Italy), 2011. Univariate analysis

	Measles			Mumps			Rubella			Varicella			Pertussis
	%	OR (95% CI)	P Value	%	OR (95% CI)	P Value	%	OR (95% CI)	P Value	%	OR (95% CI)	P Value	%	OR (95% CI)	P Value
Total	52.8 (n = 48) (95%CI 42.0–63.3)			21.6 (n = 30) (95%CI 15.1–29.4)			46.9 (n = 76) (95%CI 39.0–54.9)			14.9 (n = 10) (95%CI 7.4–25.7)			14.5 (n = 30) (95%CI 10.0–20.0)
Sex
Female	53.1	1		20.6	1		57.0	1		15.4	1		12.5	1
Male	53.9	1.03 (0.41–2.57)	0.95	25.8	1.34 (0.53–3.41)	0.53	23.4	0.23 (0.11–0.50)	<0.001^	13.3	0.35 (0.16–4.49)	0.84	20.8	1.83 (0.81–4.16)	0.15
Age (years)
20–29	75.0	1		68.8	1		77.3	1		50.0*	1		61.1	1
30–39	73.0	0.9 (0.26–3.13)	0.87	28.6	0.18 (0.05–0.62)	0.006^	64.6	0.54 (0.17–1.71)	0.29	23.8	0.31 (0.04–2.83)	0.30	11.5	0.08 (0.02–0.28)	<0.001^
40–49	15.8	0.06 (0.01–0.31)	0.001^	5.9	0.03 (0.01–0.14)	<0.001	46.3	0.25 (0.08–0.79)	0.02^	10.0	0.11 (0.01–1.28)	0.078	8.3	0.06 (0.02–0.20)	<0.001^
50+	9.1	0.03 (0.003–0.33)	0.004^	0.0	-	-	5.7	0.02 (0.003–0.10)	<0.001^	0	-	-	8.6	0.06 (0.01–0.27)	<0.001^
Profession
Nurse	47.1	1		24.4	1		51.6	1		14.3	1		15.8	1
Physician	65.0	2.09 (0.72–6.10)	0.18	12.5	0.44 (0.09–2.12)	0.31	40.6	0.64 (0.29–1.45)	0.29	0			22.0	1.50 (0.62–3.63)	0.37
Nursing assistant	33.3	0.56 (0.94–3.35)	0.53	20.0	0.78 (0.23–2.59)	0.68	26.3	0.34 (0.11–1.01)	0.051	8.3	0.55 (0.06–5.03)	0.59	0
Midwife	90.0	10.13 (1.19–85.88)	0.034^	26.7	1.13 (0.32–3.94)	0.85	81.8	4.23 (0.87–20.60)	0.075	50.0	6.00 (0.97–36.99)	0.054	10.5	0.63 (0.13–2.93)	0.55
Workplace
Emergency	54.6	1		31.4	1		46.6	1		12.5	1		18.0	1
Maternal and child	56.7	1.09 (0.40–2.95)	0.87	18.9	0.51 (0.19–1.41)	0.19	60.5	1.76 (0.79–3.91)	0.17	19.1	1.65 (0.32–8.39)	0.55	17.5	0.97 (0.40–2.38)	0.95
Intensive care	55.0	1.02 (0.33–3.11)	0.97	19.4	0.53 (0.18–1.53)	0.24	50.0	1.15 (0.48–2.72)	0.75	16.7	1.4 (0.20–9.75)	0.73	9.3	0.47 (0.14–1.53)	0.21
Infectious disease	25.0*	0.28 (0.03–2.96)	0.29	0.0			18.2	0.26 (0.05–1.29)	0.098	0			0
Operating room	0*			20.0	0.55 (0.06–5.29)	0.60	37.5	0.69 (0.15–3.16)	0.63	0*			11.1	0.57 (0.07–4.94)	0.61
Contacts per week
1–25	38.1	1		17.5	1		39.6	1		12.5	1		12.5	1
26–50	72.2	4.23 (1.09–16.4)	0.037^	28.6	1.89 (0.59–5.99)	0.28	64.3	2.75 (1.05–7.22)	0.040	26.7	2.55 (0.39–16.55)	0.33	18.6	1.60 (0.53–4.82)	0.40
>50	46.5	1.41 (0.49–4.10)	0.53	18.6	1.08 (0.38–3.08)	0.89	47.8	1.4 (0.66–2.95)	0.38	8.0	0.61 (0.08–4.82)	0.64	14.0	1.14 (0.42–3.08)	0.80
Seniority (years)
<5	80.0	1		66.7	1		65.4	1		33.3	1		37.9	1
6–10	70.8	0.61 (0.16–2.27)	0.46	34.4	0.26 (0.08–0.84)	0.024	61.1	0.83 (0.29–2.38)	0.73	33.3	1.00 (0.16–6.26)	1	22.5	0.48 (0.17–1.37)	0.17
11–20	42.9	0.19 (0.05–0.69)	0.012	8.2	0.04 (0.01–0.17)	<0.001^	50.0	0.53 (0.19–1.47)	0.22	5.3	0.11 (0.01–1.29)	0.078	6.0	0.10 (0.03–0.37)	<0.001
>20	10.0	0.03 (0.01–0.16)	<0.001	2.9	0.02 (0.002–0.13)	<0.001	29.3	0.22 (0.08–0.59)	0.003	7.7	0.17 (0.02–1.23)	0.079	8.8	0.16 (0.5–0.49)	0.001

In bold letters items significant to univariate analysis (P < 0.05). ^Significant to multivariable logistic analysis (P < 0.05). *Sample number < 5.

Furthermore, as far as rubella vaccination in women is concerned, the majority of interviewees were immunized during childhood (41.7%) or adolescence (35.0%); the remaining 23.3% reported having been vaccinated during childbearing age.

About one-third of interviewees (28.7%) stated having been immunized with combined MMR vaccine (38.3% did not answer this question).

Overall, reported vaccination coverage toward the concerned infectious diseases was significantly higher in professionals belonging to the youngest age group (from about 70% in people aged 20–29 to less than 10% in over 50). This was true for all diseases except for varicella, for which even if a gradient in percentage could be observed, the population group was too small to reach statistical significance (P < 0.1). A similar pattern could be found when considering HCWs seniority (length of service). As far as gender differences are concerned, females showed the highest reported vaccination coverage for rubella (57.0% vs 23.4%; P < 0.001). Midwives had significantly higher coverage for measles (90.0%; P < 0.05) and higher coverage for rubella (81.8%; P < 0.1) and varicella (50.0%; P < 0.1), yet not statistically significant. Among HCWs with less than 50 contacts per week statistically significant higher coverage for measles and rubella was found. No statistically significant differences in reported vaccination coverage were found among workers of different hospital departments.

HCWs reporting no history of disease or vaccination were considered as “potentially susceptible”: 9.9% to measles, 25.1% to mumps, 19.7% to rubella, 13.1% to varicella, and 40.9% to pertussis (Table 4).

Table 4. Potentially susceptible HCWs (neither history of disease nor reported vaccination). Local Health Unit of Florence (Italy), 2011. Univariate analysis.

	Measles			Mumps			Rubella			Varicella			Pertussis
	%	OR (95% CI)	P Value	%	OR (95% CI)	P Value	%	OR (95% CI)	P Value	%	OR (95% CI)	P Value	%	OR (95% CI)	P Value
Total	9.9 (n = 43)			25.1 (n = 109)			19.7 (n = 86)			13.1 (n = 57)			40.9 (n = 177)
Sex
Female	9.2	1		26.2	1		15.1	1		13.5	1		41.2	1
Male	11	1.22 (0.60–2.47)	0.59	21.1	0.75 (0.45–1.27)	0.29	33	2.78 (1.68–4.59)	<0.001^	11.9	0.87 (0.45–1.67)	0.67	38.9	0.91 (0.58–1.42)	0.68
Age (years)
20–29	15.6	1		16.1	1		15.6	1		6.3	1		23.3	1
30–39	8.6	0.51 (0.16–1.60)	0.25	29.9	2.22 (0.79–6.25)	0.13	14.5	0.92 (0.31–2.71)	0.88	13.7	2.38 (0.52–10.92)	0.27	46.6	2.86 (1.14–7.19)	0.025^
40–49	9.5	0.57 (0.19–1.67)	0.3	28.4	2.06 (0.75–5.69)	0.16	17.2	1.12 (0.40 -3.15)	0.83	10.7	1.79 (0.39–8.11)	0.45	45.6	2.75 (1.12–6.75)	0.027^
50+	9.5	0.57 (0.18–1.81)	0.34	16.2	1.01 (0.34–2.99)	0.99	31.4	2.48 (0.88–7.00)	0.09	17.1	3.10 (0.68–14.17)	0.14	30.5	1.44 (0.56–3.70)	0.45
Profession
Nurse	17.8	1		24.8	1		18.3	1		14.3	1		40.7	1
Physician	7.7	0.69 (0.29–1.65)	0.41	15.4	0.55 (0.29–1.04)	0.067	20.9	1.18 (0.65–2.14)	0.6	5.5	0.35 (0.13–0.91)	0.032^	35.2	0.79 (0.48–1.30)	0.35
Nursing Assistant	7.3	0.65 (0.22–1.94)	0.44	29.1	1.24 (0.65–2.38)	0.51	25.5	1.52 (0.77–3.02)	0.23	20	1.49 (0.71–3.26)	0.29	40	0.97 (0.53–1.76)	0.92
Midwife	3.2	0.28 (0.04–2.11)	0.22	35.5	1.67 (0.76–3.67)	0.2	6.5	0.31 (0.07–1.33)	0.12	9.7	0.64 (0.19–2.22)	0.48	54.8	1.77 (0.83–3.75)	0.14
Workplace
Emergency	9.6	1		22.4	1		19.8	1		13.4	1		41	1
Maternal and Child	9.9	1.04 (0.48–2.28)	0.92	22.9	1.03 (0.59–1.79)	0.93	13	0.61 (0.32–1.15)	0.13	13	0.97 (0.49–1.92)	0.92	35.9	0.80 (0.50–1.30)	0.37
Intensive care	10.7	1.17 (0.49–2.80)	0.85	30.5	1.52 (0.83–2.77)	0.18	19.5	0.99 (0.50–1.93)	0.97	12.2	0.90 (0.40–2.01)	0.8	48.8	1.37 (0.80–2.35)	0.26
Infectious disease	11	1.14 (0.31–4.21)	0.73	35.7	1.92 (0.81–4.54)	0.14	32.1	1.93 (0.80–4.67)	0.15	17.9	1.41 (0.48–4.11)	0.53	46.4	1.25 (0.56–2.80)	0.59
Operating Room	9.5	1.00 (0.21–4.70)	1	19.1	0.81 (0.26–2.58)	0.73	23.8	1.27 (0.43–3.73)	0.66	4.8	0.32 (0.04–2.54)	0.28	38.1	0.89 (0.35–2.26)	0.8
Contacts per week
1–25	12.5	1		31.7	1		27.9	1		13.5	1		48	1
26–50	4.6	0.34 (0.12–0.98)	0.046	18.4	0.48 (0.26–0.91)	0.025^	9.2	0.26 (0.12–0.57)	0.001^	10.1	0.72 (0.31–1.67)	0.45	32.1	0.51 (0.29–0.90)	0.019^
>50	12.6	1.01 (0.49–2.10)	0.97	26.4	0.77 (0.45–1.31)	0.33	19.8	0.64 (0.36–1.12)	0.12	12.6	0.93 (0.46–1.90)	0.84	40.7	0.74 (0.46–1.21)	0.23
Seniority (years)
<5	9.4	1		13.5	1		17	1		11.3	1		36	1
6–10	9.3	0.99 (0.30–3.30)	0.99	28	2.5 (0.97–6.42)	0.057	18.7	1.12 (0.45–2.82)	0.81	10.7	0.94 (0.31–2.87)	0.91	41.3	1.25 (0.60–2.62)	0.55
11–20	9.4	0.99 (0.33–2.97)	0.99	35.2	3.49 (1.45–8.36)	0.049^	15.6	0.91 (0.38–2.14)	0.82	14.1	1.28 (0.48–3.43)	0.62	49.2	1.72 (0.88–3.38)	0.11
>20	10.3	1.10 (0.39–3.12)	0.86	19.4	1.55 (0.64–3.74)	0.329	23.4	1.50 (0.67–3.32)	0.32	13.7	1.25 (0.48–3.23)	0.65	35.4	0.98 (0.51–1.88)	0.94

In bold letters items significant to univariate analysis (P < 0.05). ^Significant to multivariable logistic analysis (P < 0.05). *Sample number < 5.

Statistically significant gender differences were found only for rubella (male 33.0% vs female 15.1%). A statistically significant higher percentage of HCWs potentially susceptible to pertussis was observed in those aged between 30 and 49.

As for the profession, the percentage of potentially susceptible physicians was lower for varicella (5.5%; P < 0.05) and mumps (15.4%; P < 0.1).

A lower percentage of potentially susceptible subjects was also found among HCWs who came in contact with 26–50 patients per week. These data were statistically significant for all diseases except for varicella.

As far as mumps is concerned, a higher percentage was observed among those with 6–20 y of service in health care.

No statistically significant differences in vaccination coverage were found among HCWs of different hospital departments.

When asked why they did not undergo immunization only about half of interviewees (47–67%) answered the question. The main reported reasons were lack of active offer of immunization (from 22% for varicella to 48% for pertussis), personal vaccination opposition (from 14% for rubella and pertussis to 33% for varicella), and in the case of rubella the presence of specific protective antibodies (27%) (Fig. 1).

Figure 1. Reported reasons for no vaccination in a sample of HCWs. Local Health Unit of Florence (Italy), 2011.

Risk perception and willingness to undergo immunization

When considering potentially susceptible HCWs, 41.9% felt at risk for measles, 39.5% for mumps, 32.2% for pertussis, 31.6% for varicella, 27.9% for rubella.

A lower risk perception was found in all professionals employed in Intensive care units. These data were statistically significant for mumps (OR = 0.24, 95% CI: 0.07–0.77), rubella (OR = 0.92, 95% CI: 0.01–0.79), and pertussis (OR = 0.34, 95% CI: 0.13–0.89) (P < 0.05). As far as mumps is concerned, a statistically significant higher risk perception was observed among HCWs who came in contact with more than 50 patients per week (OR = 2.17, 95% CI: 0.87–5.45) (P = 0.01).

Overall, 27.5% of potentially susceptible HCWs would undergo vaccination for mumps, 25.6% for measles and pertussis, 20.9% for rubella, and only 15.8% for varicella (Table 5).

Table 5. Willingness to undergo immunization among potentially susceptible HCWs. Local Health Unit of Florence (Italy), 2011. Univariate analysis

	Measles			Mumps			Rubella			Varicella			Pertussis
	(%)	OR (95% CI)	P value	(%)	OR (95% CI)	P value	(%)	OR (95% CI)	P value	(%)	OR (95% CI)	P value	(%)	OR (95% CI)	P value
Total	25.6 (n = 11)			27.5 (n = 30)			20.9 (n = 18)			15.8 (n = 9)			25.6 (n = 45)
Feel at risk
No	16	1		16.7	1		11.3	1		10.3	1		15.8	1
Yes	38.9	3.34 (0.80–13.94)	0.098	44.2	3.96 (1.64–9.58)	0.002^	45.8	6.65 (2.16–20.46)	<0.001^	27.8	3.37 (0.78–14.50)	0.1	46.4	4.61 (2.25–9.45)	<0.001^
Sex
Female	30	1		28.2	1		20.4	1		18.2	1		22	1
Male	16.7	0.47 (0.08–2.57)	0.38	26.1	0.90 (0.32–2.55)	0.84	22.2	1.11 (0.39–3.18)	0.84	7.7	0.38 (0.04–3.31)	0.38	38.1	2.19 (1.04–4.61)	0.040^
Age (years)
20–29	80	1		40	-	-	40	1		0*	-	-	28.6	-	-
30–39	40	0.17 (0.01–2.09)	0.17	40	1		29.4	0.63 (0.08–4.96)	0.66	18.8	1		31.5	1
40–49	6.3	0.02 (0.00–0.33)	0.007^	16.7	0.3 (0.11–0.83)	0.020^	13.8	0.24 (0.03–1.92)	0.18	16.7	0.87 (0.15–5.06)	0.87	27.6	0.83 (0.39–1.78)	0.64
50+	20	0.06 (0.004–0.92)	0.043^	29.4	0.63 (0.18–2.17)	0.46	18.2	0.33 (0.05–2.45)	0.28	11.1	0.54 (0.08–3.74)	0.53	9.4	0.23 (0.06–0.84)	0.027
Profession
Nurse	22.2	1		24.2	1		19.6	1		8.33	1		23	1
Physician	42.9	2.63 (0.46–15.1)	0.28	50	3.13 (0.95–10.38)	0.062	21.1	1.10 (0.29–4.11)	0.89	40	7.33 (0.86–62.60)	0.069	37.5	2.01 (0.86–4.72)	0.11
Nursing Assistant	50.0*	3.5 (0.40–30.34)	0.26	43.8	2.44 (0.77–7.67)	0.13	35.7	2.28 (0.61–8.50)	0.22	36.4	6.29 (1.14–34.57)	0.035^	27.3	1.26 (0.44–3.58)	0.67
Midwife	0*	−	−	9.1	0.31 (0.04–2.65)	0.29	0*	−	−	0*	−	−	17.7	0.72 (0.19–2.72)	0.63
Workplace
Emergency	33.3	1		34.4	1		38.7	1		19.1	1		34.4	1
Maternal and Child	15.4	0.36 (0.06–2.31)	0.28	30	0.82 (0.29–2.34)	0.71	11.8	0.21 (0.04–1.09)	0.064	23.5	1.31 (0.27–6.24)	0.74	23.9	0.6 (0.26–1.41)	0.24
Intensive care	33.3	1 (0.17–5.77)	1	12	0.26 (0.06–1.05)	0.059	0	−		0	−	−	15.4	0.16 (0.02–1.30)	0.09
Infectious disease	33.3	1 (0.72–13.87)	1	30	0.82 (0.18–3.76)	0.8	44.4	1.27 (0.28–5.68)	0.76	20	1.06 (0.92–12.28)	0.96	7.7	0.16 (0.02–1.30)	0.04
Operating Room	0*	−	−	25.0*	0.64 (0.06–6.82)	0.71	0	−		0*	−	−	50	1.91 (0.44–8.38)	0.39
Contacts per week
1–25	38.5	1		21.2	1		13.8	1		14.3	1		18.8	1
26–50	20	0.4 (0.03–4.68)	0.47	40	2.48 (0.73–8.42)	0.15	10	0.69 (0.07–7.10)	0.76	18.2	1.33 (0.16–11.36)	0.79	25.7	1.5 (0.53–4.28)	0.45
>50	21.7	0.44 (0.10–1.98)	0.29	31.3	1.69 (0.60–4.75)	0.32	36.1	3.53 (1.01–12.40)	0.049	21.7	1.67 (0.28–10.03)	0.58	33.8	2.21 (0.93–5.28)	0.074
Seniority (years)
<5	100	−	−	57.1	1		33.3	1		16.7	1		38.9	1
6–10	57.1	1		57.1	1 (0.18–5.63)	1	42.9	1.5 (0.26–8.58)	0.65	37.5	3 (0.23–39.61)	0.83	45.2	1.29 (0.40–4.22)	0.67
11–20	0	−	−	20	0.19 (0.04–0.99)	0.049^	20	0.5 (0.09–2.93)	0.44	27.8	1.92 (0.18–20.82)	0.54	17.5	0.33 (0.11–1.05)	0.06
>20	11.1	0.09 (0.01–0.76)	0.027	14.7	0.13 (0.02–0.76)	0.024^	12.2	0.28 (0.05–1.48)	0.13	0	−	−	21.3	0.43 (0.14–1.32)	0.14

In bold letters items significant to univariate analysis (P < 0.05); ^Significant to multivariable logistic analysis (P < 0.05); * sample number < 5.

Risk perception resulted strongly associated with willingness to get vaccinated. For instance, a statistically significant higher percentage of potentially susceptible HCWs would vaccinate if feeling at risk for mumps, rubella, and pertussis (44–46%). A similar pattern can be observed also for measles and varicella, although the population group is too small to reach statistical significance (P < 0.1).

Willingness to undergo immunization was lower in HCWs aged over 40, with statistical significance for measles (6.3%), mumps (16.7%), and in HCWs aged over 50 for pertussis (9.4%).

As far as profession is concerned, potentially susceptible nursing assistants would get vaccinated against varicella in a statistically higher percentage (36.4%; P < 0.05); similarly, higher percentage of potentially susceptible physicians would get vaccinated for varicella and mumps yet no statistically significance was achieved.

Furthermore, potentially susceptible HCWs who came in contact with more than 50 patient per week would get the vaccine in a higher percentage for rubella (36.1%; P < 0.05) and for pertussis (33.8%; P < 0.1).

Interviewees were finally asked about their opinion on vaccines. The great majority showed a positive opinion: 28% considered vaccines absolutely useful and 57% thought that some vaccinations are useful to prevent serious diseases. No more than 10% of the whole sample expressed a negative opinion, declaring personal opposition to vaccines (6%), or asserting that vaccinations are dangerous because of the high risk of adverse events (3%) (Fig. 2).

Figure 2. HCWs’ attitude toward vaccinations (n = 436). Local Health Unit of Florence (Italy), 2011.

Discussion

Over the past decades, reinforcement of safety in health care facilities has been a basic component of clinical practice. Vaccination of HCWs is justified for self-protection, as well as for protection of susceptible patients, and indirect protection of general population through herd immunity.^17,30

In the present study, a questionnaire was used to collect information on attitudes and behaviors regarding vaccinations against measles, mumps, rubella, varicella, and pertussis of HCWs working in the Local Health Unit of Florence. HCWs employed in high risk department (Intensive Care Unit, Maternal and Child, Infectious Disease, and Emergency) were the target of our survey. High level of immunity against those specific diseases is considered particularly important for healthcare professionals.

As recommended by the CDC, HCWs without evidence of immunity should be provided with 2 doses of MMR for measles and mumps protection, one dose of MMR for rubella protection and 2 doses of varicella vaccine 4–8 wk apart for varicella protection. As far as pertussis protection is concerned HCWs not previously vaccinated with Tdap, should receive a single dose of Tdap as soon as feasible, regardless time elapsed from the last dose of tetanus-containing vaccine.²⁹

The Global Pertussis Initiative recommends adults, who are in close contact with infants, to undergo selective vaccination or booster vaccination if time since the last immunization exceeds 10 y,³¹ since infected adults may act as a reservoir of infection and cause severe diseases in newborns and partially immunized infants.³²

In Italy, immunization is regulated since 1994 by a national law which establishes that employers should provide their employees with adequate immunization to protect both workers themselves and individuals they may come in contact with.^33,34 In addition, HCWs immunization for the above mentioned illnesses is recommended by the current National Immunization Schedule 2012–2014.³⁵

Nevertheless, our study confirms that reported vaccination coverage for non-compulsory vaccinations is low in HCWs of Florentine area, particularly for mumps, rubella, and pertussis, in line with what has been shown by other authors in Italy^1,36,37 and in Europe too.³⁸ Despite the low reported vaccination coverage, some encouraging findings could be highlighted. First, younger professional are more vaccinated compared with older professionals, which might be explained by the fact that these vaccinations are currently offered to children and adolescents. Second, females show significantly higher reported vaccination coverage for rubella compared with men. This is consistent with the fact that in Italy rubella vaccination was offered free of charge to women in the adolescence and childbearing age since the seventies. Rubella vaccination was also recommended by the Italian Ministry of Health, in both National Plans for the Elimination of Measles and Congenital Rubella in 2003 and 2011, respectively.^39-41

A limitation to our results for rubella vaccination reported by women is that it was not specifically investigated the number of women who did not get vaccinated because of positivity to rubeo-test.

However, in our sample, among unvaccinated women positivity to rubeo-test was the reason of no vaccination in 41.4% (95% CI: 25.5–61.1%).

In a sero-epidemiological study performed on sera collected from general population of Tuscany (Italy) susceptibility to rubella was investigated in a sample of childbearing age women and the recommended threshold of susceptibility for the elimination of congenital rubella had still not been reached confirming the high risk to acquire infection in fertile women.⁸

Another encouraging result is that reported vaccination coverage for measles, mumps, rubella, and varicella, although insufficient, is higher in midwives. Unfortunately, this was not the case for pertussis, for which further improvements in prevention strategies are needed, since it represents a potentially fatal disease for infants.⁴²

Our results demonstrate that susceptible HCWs (without history of disease or vaccination) are a relevant part of the hospital workforce in Florence. Nevertheless, in the case of measles and varicella the absolute number of potentially susceptible HCWs was very low, due to the high percentage of interviewees with a history of these diseases. Particularly for measles, a relatively high “reported vaccination coverage” also contributed to the estimated low susceptibility.

Another key finding was that less than a half of potentially susceptible HCWs felt at risk for the previous mentioned vaccine-preventable diseases. This was particularly true for professionals employed in Intensive Care Units, who had significantly low perceived risk about all diseases, despite they work in contact with critical patients.

Besides, the percentage of potentially susceptible HCWs who would get vaccinated was less than 30%. The multivariate analysis indicated that feeling at risk for a particular illness was a significant predictor of willingness to undergo vaccination. Therefore efforts should be made to raise HCWs awareness of vaccine-preventable diseases risks. As confirmed by our study, HCWs general opinion about vaccines was positive in the great majority of cases. Efforts in improving HCW knowledge, attitude, and behavior should be enhanced. Possible reasons of low compliance to vaccination might include the lack of the staff knowledge about vaccination's possible benefits, as already highlighted by other Italian authors.^43,44

Low vaccination uptake for non-compulsory vaccinations could be explained to some extent by the fact that these vaccinations had not always been proposed to HCWs. Employers (i.e., hospital direction) and occupational physicians should ensure that even not-compulsory vaccinations are indeed offered. In a recent Italian study, the analysis of the determining factors for HCWs vaccination revealed that there was a problem in the offer and the adoption of preventive measures.³⁷ Vaccinations should be offered especially to newly hired HCWs with negative serological results for antibodies against specific viruses.^36,45 In addition, even medical students should be screened and immunized, if susceptible, before get in contact with patients.⁴³

The main limitation of this study is that a baseline assessment on HCWs attitude toward vaccination was not performed before the training course involving HCWs working in all the 6 hospitals of the LHU of Florence. Moreover, it is not known how many HCWs have been vaccinated in the months following the study, but we obtained that, after this study, all newly hired HCWs would be screened by the occupational medicine service and they would be vaccinated against specific infectious diseases, in case of negative serological results for antibodies. There are some other potential limitations in the present work that should be considered when interpreting the results. First, the number of interviewees with a history of disease was high, especially for measles and varicella. Therefore the small number of potentially susceptible HCWs could explain the low precision of our estimates for certain subgroups (e.g., susceptibility to measles or risk perception in potentially susceptible subjects to measles, rubella, and varicella).

Second, no serologic screening of personnel was performed. Thus, our vaccination coverage estimates were performed on the number of HCWs reporting no history of disease. It is known that individuals’ recall is not always reliable.^36,46 In a study performed to investigate the immune status of HCWs against measles, rubella, mumps, and varicella zoster (MMRV) in Turkey the positive prediction value for the history of varicella was 100%, whereas it was 92% for MMR.⁴⁷ For effective prevention of nosocomial infection, immunization status against these infectious diseases should be documented for all HCWs, through serological screening, and susceptible workers should be vaccinated.

Moreover, at least 2 factors may bias some outcomes. Vaccination coverage estimate was based on individual's recall, which may result in both over- or under-estimation. Furthermore, 27% of the target population did not participate to the survey, and this group may have been less concerned with immunization or against vaccinations. This factor may have led to an overestimation of our reported vaccination coverage, which highlights once more the need to implement further strategies to increase vaccination coverage of HCWs even for non-mandatory vaccinations.⁴⁸

Finally, as far as pertussis is concerned, our questionnaire did not include information about age of infection or booster vaccination data. Since immunity to pertussis begins to wane 4 to 20 y after natural infection or vaccination acquired immunity, HCWs susceptible to pertussis may be even higher.⁴⁹ Moreover, even if no serologic correlate of protection after immunization exists, subjects with high antibody levels against pertussis antigens are less likely to develop the disease.⁵⁰ Studies on the level of immunity in HCWs working in hospitals of the Florentine area could be performed in order to identify susceptible subjects in these setting at high risk of infection and transmission and finally offer them immunizations even for no mandatory vaccinations.

Conclusions

Failure to protect HCWs against these potentially serious infections has health and safety implications both for health professionals and the patients they care for. Overall, our study revealed a generally positive attitude toward immunization in health care personnel working in Florentine hospitals. One of the main reasons of the relatively low coverage was indeed lack of active offer of vaccines. Employers have the duty of care to staff and patients by providing them with protection through vaccinations when vaccines are available. Therefore, stronger recommendations and adequate training, including specific courses on vaccine preventable diseases, should address HCWs in order to increase their vaccination coverage. More information should be made available to HCWs on the benefits of vaccination and efforts to encourage vaccination uptake should be made.

Materials and Methods

Source population

A cross-sectional survey among the physicians, nurses, midwives, and nursing assistants employed in all the 6 public hospitals of the Local Health Unit of Florence was performed. Administrative staff, HCWs who did not belong to these 4 professional groups (i.e., lab technicians, X-ray technicians), students, and trainees were not included in the study.

In order to focus on those HCWs who have a higher risk of acquiring a vaccine-preventable disease among those previously mentioned, it was decided to include in the survey professionals working in the following hospital departments: Emergency, Maternal and Child Healthcare, Intensive Care Unit, Infectious Diseases, and Operating Room.

Data collection

In January 2011 a 1-d not mandatory training course, addressed to all HCWs working for the Local Health Unit of Florence, was organized at the Department of Health Sciences (University of Florence). The training course aimed at update the knowledge of HCWs on the epidemiology of infectious diseases in international, national and regional context, particularly focusing on measles, rubella, pertussis, varicella, and mumps. Moreover, the surveillance network and the strategies to prevent the above mentioned diseases were illustrated. A training session was specifically dedicated to the risk perception assessment in HCWs and to their attitude toward immunization. Finally, HCWs were informed about the importance and the opportunity of reaching adequate vaccination coverage, for which dedicated vaccination stands would have been arranged in the following days in the 6 hospitals in the Florentine area. In May 2011 a questionnaire was sent to professionals working in the selected departments. Each questionnaire was accompanied by an introductory letter and a leaflet describing the regional epidemiology of the above mentioned infectious diseases. Completed questionnaires were then retrieved between June and October 2011.

Data were collected by a self-administered, anonymous questionnaire: demographic and administrative data, as well as information on vaccination and history of measles, mumps, rubella, varicella, and pertussis were collected. The questionnaire also investigated HCWs personal opinion on the risks related to those specific diseases, on vaccination usefulness and on their willingness to undergo immunization. All HCWs available to be vaccinated were invited to inform their responsible for hospital ward in order to verify the individual need to be immunized.

Statistical analysis

Data were coded and entered in a Microsoft Access database, and all data management and analyses were performed with STATA 11.0® (Statacorp).

For the calculation of the reported vaccination coverage, the numerator was based on the number of HCWs who declared being vaccinated and the denominator resulted from the number of professionals reporting no history of disease. HCWs were considered to be up-to-date for a vaccine when they declared being vaccinated, therefore only HCWs reporting no history of disease or vaccination were considered potentially susceptible. No serological confirmation was performed for no one of the participants.

Reported vaccination coverage, susceptibility to the previously mentioned infectious diseases, infectious diseases risk perception, and willingness to undergo immunization between the different subgroups were tested using the Chi-squared test. These items were analyzed using logistic regression modeling with the event such as vaccination coverage coded as binary variable (Yes/No).

Variables with a significance level of P < 0.1 in the univariable analysis, as well as variables considered to be potential confounders, whatever their level of statistical association in the univariable analysis was, were then entered in the multivariable model. Variables were considered statistically significant when the P value was less than 0.05.

Disclosure of Potential Conflicts of Interest

No potential conflicts of interest were disclosed.

Acknowledgments

The authors would like to thank Dr Letizia Sommani and her colleagues working at the Occupational Medicine Service of the LHU of Florence, for their support in the current research and their commitment in carrying out their work.

Additional information

Funding

Moreover, the authors would like to thank the Tuscany Regional Health Authorities for the financial support in the realization of this study.