Improved influenza vaccination coverage among health-care workers: evidence from a web-based survey in China, 2019/2020 season

ABSTRACT

To understand influenza vaccination and its correlates among health-careworkers (HCWs) during the 2019/2020 season in China, we used a self-administeredelectronic questionnaire to collect information on demographics, occupational characteristics, influenza vaccination status and access to free vaccination on the “Breath Circles”, a Chinese media platform for respiratory medical professionals. The reported influenza vaccine coverage among HCWs during this season was 67%, with more HCWs in a workplace with free vaccination than those with no free vaccination (79% vs.34%,p < .001). The influenza vaccine coverage among HCWs who were required or encouraged to get vaccinated by the workplace was significantly higher than that without any intervention measures (80% & 70 vs.39%,p < .001). The vaccine coverage in the workplaces with free and required vaccination simultaneously was highest compared to that with neither free vaccination nor any intervention measures (OR = 14.86, 95% CI: 10.93–20.20). The influenza vaccination coverage of HCWs in high-riskdepartments was significantly higher than that of other departments (70% vs.58%,p =.023). HCWs’ vaccine coverage was related to personal opinions and attitudes toward influenza or influenza vaccines, as well as other constraints such as availability of influenza vaccines, workplace regulations, and access to free vaccines.

KEYWORDS:

• Health-careworkers
• influenza
• influenza vaccines
• vaccination status

1. Introduction

Annual seasonal influenza epidemics result in substantial morbidity and mortalityglobally.¹The Global Burden of Disease Study 2017 shows that 0.26% (95% CI: 0.20–0.32) of the global death toll can be attributed to influenza, with nearly one-thirdoccurring in India, China andRussia.²In China, influenza was associated with an average of 2.5 excess influenza-like-illness(ILI) consultations per 1,000 person-yearseach year from 2006 to2015³and an annual mean of 88,100 influenza-associatedexcess respiratory deaths from 2010 to2015.⁴Due to occupational exposure, health-careworkers (HCWs) have a greater chance to be infected with influenza virus, probably providing a source causing nosocomial transmission. A meta-analysisfound that among all influenza-infectedpersons who were not vaccinated, the influenza incidence rate of HCWs was 18.7%, with a RR of 3.4 compared with people in other workplaces not associated with health care; among all symptomatic influenza-infectedpersons who were not vaccinated, the incidence rate of HCWs was 7.5, with a RR of1.5.⁵Influenza vaccination can not only prevent HCWs from influenza and its complications but also reduce their absence fromwork.⁶Furthermore, vaccination among HCWs can also indirectlyprotect vulnerable populations and high-riskpatients in health-carefacilities.⁷

China has made great efforts in pushing forward influenza vaccination coverage for HCWs. In October 2018, China National Health Commission issued an official document, requiring medical institutions at all levels to provide their staff with free influenza vaccination before influenza season and especially ensure that all HCWs in high-riskdepartments, such as respiratory or infectious diseases departments, werevaccinated.⁸In the Technical Guidelines for Seasonal Influenza Vaccination in China (2019–2020), issued by the Chinese Center for Disease Control and Prevention, HCWs were the priority group for influenzavaccine.⁹However, not all hospitals followed these documents well. The influenza vaccine coverage among HCWs was only 11.6% in China in2018–2019.¹⁰This study aims to investigate the influenza vaccination among HCWs during the2019–2020 influenza season, to find out whether the strategies of free vaccination and workplace vaccination requirement are associated with higher influenza vaccination coverage in health-caresettings, and to understand the attitudes of HCWs toward influenza vaccination.

2. Materials and methods

2.1. Study design

A cross-sectional study was conducted among HCWs from April 9 to April 13, 2020, on the “Breath Circles” through a questionnaire survey powered by Wenjuanxing (wjx.cn). The “Breath Circles” is a WeChat-basedmedia platform for respiratory medical professionals, covering 29 provincial regions in China with 154,000 subscribers who are working in various fields related to respiratory medicine, such as pneumology department, infectious diseases department, emergency department and pediatrics department. Wenjuanxing is a program for questionnaire designing with similar functions as Amazon Mechanical Turk. Previous studies have shown that years of work, departments of work, workplace regulations and access to free vaccination can be associated with influenza vaccinecoverage.^10–12Besides, other researches have shown that the views of HCWs on the benefits, effectiveness, and side effects of influenza vaccine could affect their vaccineuptake.^13,14The content of our questionnaire includes occupations, work departments, influenza vaccination status, reasons for vaccination receipt/non-receipt,workplace regulation, vaccination policy, etc.

The sample size was estimated by the calculation formula of simple random samples, and the estimated sample size was 3,940 according to previous reported vaccination rate of 11.6% amongHCWs,¹⁰α = 0.05, allowable error was 1%, and Zα = 1.96. Considering the possible nonconforming feedback, the sample size should be at least 4,344, with a margin of 10%.

2.2. Data collection

We posted a questionnaire link on the Breath Circles, and all the survey items were compulsory. HCWs who received the link might forward it to their colleagues, but each participant could answer once. For certain questions, respondents can select more than one option with no rank order required.

We categorized respiratory department, infectious diseases department, emergency department, pediatrics department, intensive care unit (ICU)/intensive medicine department, fever clinic, geriatrics department, obstetrics and gynecology department as “high-riskdepartments”, with the remaining departments as “otherdepartments”.⁸Influenza vaccine coverage refers to the proportion of people who received influenza vaccine. Those who did not remember whether they had been vaccinated were excluded in the denominator when calculating the coverage.

We defined vaccination policy and workplace regulations on vaccination as follows: (1) The vaccination policy was divided into two types, namely free and self-pay.Free vaccination policy: the cost of vaccines and vaccination services is borne by the workplace, including payment by the workplace directly or the employee gets reimbursement after vaccination; Self-payvaccination policy: the cost of vaccines and vaccination services is borne by the recipients. (2) Workplace regulations on vaccination were divided into four types, namely required, encouraged, no intervention, and unknown. Required vaccination: hospitals issued official document or regulation to ask employees to get compulsory vaccination; Encouraged vaccination: hospitals motivated employees to receive influenza vaccine through the way of health education or health knowledge dissemination, e.g. influenza vaccine knowledge lectures or notice of time and place to get vaccinated; No intervention: hospitals neither required nor encouraged employees to get vaccinated; Unknown: respondents were not aware of any regulations on influenza vaccine in the workplace.

2.3. Statistics analysis

A new variable was created combining free vaccination policy and workplace regulation. This new variable was a categorical variable with 12 classes, namely no free policy with no intervention/encouragement/requirement/unknown, free policy with no intervention/encouragement/requirement/unknown, unknown whether it was free with no intervention/encouragement/requirement/unknown.

The survey results were imported into MS Excel and analyzed by SPSS and SAS. All the categorical variables were compared by using chi-squaretest (α = 0.05). Binary logistic regression models were used to analyze the factors associated with the vaccination among HCWs. The dependent variable was whether vaccinated from August 2019 to April 2020. The independent variables were occupation, title, hospital level, department, GDP per capita, workplace regulations, free vaccination policy, and the new variable mentioned above.

2.4. Human subjects review

The study protocol and questionnaire were approved by the Ethical Review Committee of Chinese Center for Disease Control and Prevention (No.201901–01, China CDC, Beijing, China). All participants provided verbal informed consent to be interviewed.

3. Results

3.1. Demographics of study population

This survey collected 4,595 valid questionnaires, covering all the 29 provinces (autonomous regions, municipalities directly under the Central Government) in China. Among the 4,595 respondents, 1,667 (36%) worked in primary hospitals, 2,027 (44%) in secondary hospitals and 901 (20%) in tertiary hospitals; 3366 (73%) were in high-riskdepartments and 1129 (27%) were in other departments; 1332 (29%) were clinicians, 1283 (28%) were nurses, 1700 (37%) were medical technicians and 280 (6%) were of other categories.

3.2. Influenza vaccination status of HCWs and associated factors

Of the 4,595 respondents, 229 people did not remember whether they had been vaccinated against influenza during the period aforementioned. The vaccination coverage of this survey was 67% (2927/4366). Among these influenza vaccine recipients, 38.1% (1116/2927) received direct free vaccination, 30.2% (886/2927) got reimbursement from their workplace after vaccination, 21.1% (618/2927) received self-paidvaccination 10.1% (297/2927) received health insurance reimbursement after vaccination, and 0.3% (10/2927) was other situations. The vaccination coverage of workplaces with free vaccination policy (79%) was significantly higher than that with no free vaccination policy (34%) (p < .001). Likewise, HCWs with workplace requirement (80%) or encouragement (70%) for vaccination had higher vaccination coverage than those without workplace requirement or encouragement (39%) (p < .001). The influenza vaccination coverage of HCWs in high-riskdepartments (70%) was significantly higher than that of other departments (58%) (p =.023). See Table 1 for details.

Table 1. Influenza vaccination coverage of 4366 HCWs in 2019/2020 influenza season

Characteristic	Category	N	Vaccinated	Vaccination coverage (%)	P (chi-squaretest)	OR (95%CI)
Occupation	Clinicians	1292	783	61	0.16	Ref
	Nurse	1199	821	68		1.16 (0.95–1.40)
	Medical technicians^a	1625	1177	72		1.22 (1.02–1.47)
	Others	250	146	58		1.00 (0.72–1.41)
Professional title^b	Primary	743	484	65	0.27	Ref
	Middle	2506	1724	69		1.16 (0.95–1.42)
	Senior	1054	690	65		1.18 (0.94–1.49)
	Unknown	63	29	46		0.79 (0.43–1.44)
Hospital level^c	Tertiary	867	559	64	<0.001	Ref
	Secondary	1918	1240	65		0.72 (0.59–0.87)
	Primary	1581	1128	71		0.93 (0.75–1.14)
Working departments	Others	1141	666	58	0.0023	Ref
	High-riskdepartments^d	3225	2261	70		1.30 (1.10–1.53)
Province by GDP per capita^e	Low	911	610	67	0.60	Ref
	Middle	1342	896	67		1.11 (0.91–1.36)
	High	2113	1421	67		1.06 (0.88–1.28)
Workplace’s regulation	No intervention	583	225	39	<0.001	Ref
	Encourage	2320	1622	70		1.95 (1.57–2.43)
	Required^f	1317	1055	80		2.81 (2.20–3.59)
	Unknown	146	25	17		0.53 (0.32–0.86)
Free vaccination	No	931	314	34	<0.001	Ref
	Yes	3229	2561	79		5.34 (4.49–6.34)
	Unknown	206	52	25		0.79 (0.55–1.14)

a: Medical technicians include inspection, imaging, ultrasound, electrocardiogram, pharmacy, etc. Others include scientific research, administration and logistics personnel.

b: Primary: equals to resident physician; Middle: equals to Chief physician; Senior: equals to Professor.

c: Primary hospitals: mainly refer to rural township hospitals and community health service centers that provide prevention, treatment, healthcare and rehabilitation services directly to communities of a certain population in China. Secondary hospitals: mainly refer to county-levelhospitals that provide comprehensive medical and health-careservices to multiple communities and undertake certain teaching and scientific research tasks. Tertiary hospitals: hospitals above the regional level that provides high-levelspecialized medical and health-careservices and carries out higher education and scientific research tasks to multiple regions.

d: High-riskdepartments include respiratory department, infection department, emergency department, pediatrics department, ICU/intensive medicine department, fever clinic, geriatrics department, obstetrics and gynecology department.

e: In terms of GDP per capita, provinces are divided into three levels: low, middle and high. Low for Anhui, Qinghai, Jiangxi, Shanxi, Tibet, Heilongjiang, Guangxi, Guizhou, Yunnan, Gansu; Middle for: Chongqing, Shaanxi, Liaoning, Jilin, Ningxia, Hunan, Hainan, Henan, Xinjiang, Sichuan, Hebei; High for: Beijing, Shanghai, Tianjin, Jiangsu, Zhejiang, Fujian, Guangdong, Shandong, Inner Mongolia, Hubei.

f: Required vaccination means hospitals issued official document or regulation to ask employees to get compulsory vaccination, but HCWs who have not received influenza vaccination will not be punished.

3.3. Correlates of influenza vaccination

The correlates of the influenza vaccination coverage were analyzed by binary logistic regression. HCWs’ vaccination status was better when their workplace provided free vaccination policy (OR = 5.34, 95% CI: 4.49–6.34), required (OR = 2.81, 95% CI: 2.20–3.59) or encouraged influenza vaccination (OR = 1.95, 95% CI: 1.57–2.43). HCWs from high-riskdepartments (OR = 1.30, 95% CI: 1.10–1.53) had a higher coverage than those from other departments (Table 1). Taking HCWs from workplaces with no free vaccination policy and regulations as the reference group, that of free vaccination policy combined with vaccination requirement indicated the highest vaccination coverage (OR = 14.86, 95% CI: 10.93–20.20), followed by the combination of free vaccination policy and encouraged vaccination (OR = 10.30, 95% CI: 7.74–13.71) (Table 2).

Table 2. Association between different interventions and HCWs’ influenza vaccination status

Free policy	Policy of workplace	N	Vaccinated	Coverage (%)	OR (95%CI)*
Yes	Require	1171	984	84.03	14.86 (10.93–20.20)
	Encourage	1835	1436	78.26	10.30 (7.74–13.71)
	No intervention	208	132	63.46	5.10 (3.47–7.48)
	Unknown	15	9	60.00	4.53 (1.55–13.21)
No	Require	129	64	49.61	2.92 (1.88–4.52)
	Encourage	409	158	38.63	1.87 (1.34–2.60)
	No intervention	314	79	25.16	Ref
	Unknown	79	13	16.46	0.60 (0.32–1.16)
Unknown	Require	17	7	41.18	2.04 (0.74–5.61)
	Encourage	76	28	36.84	1.77 (1.04–3.04)
	No intervention	61	14	22.95	0.88 (0.46–1.69)
	Unknown	52	3	5.77	0.18 (0.06–0.61)

* The independent variables of binary Logistic regression were occupation, title, hospital level, department, GDP per capita, and combination of workplace policy and regulations

3.4. Reasons for influenza vaccinationreceipt/non-receipt

Among the 2,927 vaccinated HCWs, 65% worried about infecting others with influenza, 51% worried about catching influenza and 49% could access to influenza vaccine conveniently (Table 3). It is worth noting that 29% (964/3366) of HCWs from high-riskdepartments had not been vaccinated, which they mainly attributed to three causes: too busy in work (50%), influenza was not severe and it is not necessary to get vaccinated (41%), being worried about adverse reactions to influenza vaccine (36%) (Table 4).

Table 3. Reasons for influenza vaccination among health-careworkers in China, 2019–2020

Reasons for vaccination*	N (2927)	Percentage (%)
Being worried that influenza will spread to others	1904	65
Being worried about having influenza	1505	51
Convenient vaccination site	1436	49
Required by the workplace	1235	42
Recommendations of the Guide 2019	1192	41
Free vaccination	754	26
Had influenza last winter	435	15
Influenza affects work	320	11

*These reasons are not mutually exclusive.

Table 4. Reasons for not getting influenza vaccination among health-careworkers in high-riskdepartments in China,2019–2020

Reasons for not being vaccinated*	N (964)	Percentage (%)
Too busy in work	479	50
Influenza won’t cause severe illness	395	41
Being worried about adverse reactions	346	36
Do not know when to vaccinate	334	35
Influenza vaccine is not effective	319	33
Do not want to pay for the vaccine	313	32
Inconvenient vaccination site	260	27
Do not know where to vaccinate	215	22
Having contraindications	155	16
Pregnant or lactating women	76	8

*These reasons are not mutually exclusive.

4. Discussion

One year after China’s National Health Commission released the official document, we saw a relatively high influenza vaccine coverage among HCWs during 2019/2020 season. Free vaccination policy combined with vaccination requirement was associated with a higher influenza vaccination coverage. Influenza vaccination can not only protect HCWs from influenza virus infection and help maintain the normal operation of health-caresystem but also reduce the risk of nosocomial infections and the spread of influenza that benefits those who have no access to vaccination. In 2017, 119 WHO countries and regions reported having influenza vaccines, and 102 countries reported having vaccination policies forHCWs.¹⁵To reduce the morbidity and mortality of HCWs and patients related to influenza, and for fewer absences in number and duration, all HCWs without contraindications shall be vaccinated with influenza vaccine before the influenza season comes annually. Our research showed that the influenza vaccine coverage of HCWs in 2019/2020 influenza season was 67%. In the 2017/2018 influenza season, the influenza vaccination coverage among HCWs in the United States reached78.4%.¹⁶In the three influenza seasons from 2015 to 2018, the influenza vaccination coverage of HCWs in the 12 EU member states ranged from 15.6% to63.2%.¹⁷

Other study indicates that appropriate policies might promote influenza vaccination coverage in a shortterm.¹⁸In this survey, the vaccine coverage was higher in workplaces with free vaccination policy than those without free vaccination policy, and the coverage was higher when vaccination is required or encouraged by the workplaces. Besides, the result of logistic regression analysis showed that the combination of free vaccination policy and vaccination requirement was an effective strategy to promote vaccination coverage among HCWs. In the United States, the influenza vaccination coverage among HCWs was the highest (94.8%) when vaccination was required by workplaces and the lowest (47.6%) given no required, encouraged or provided on-sitevaccination.¹⁶Under the condition of free policy combined with high vaccine availability, the coverage among HCWs in Xining City, China, increasedsignificantly.¹⁹

HCWs’ vaccination behavior was related to the following aspects: complacency, convenience and confidence, such as physical availability, affordability and geographical accessibility and HCWs’ attitudes toward influenza and influenzavaccines.²⁰The top three reasons for HCWs to get vaccinated in this survey were being worried about infecting others, being worried about catching influenza, and being access to influenza vaccine conveniently. Our survey results also show that HCWs from high-riskdepartments were more likely to receive influenza vaccines than those from other departments. The reasons for this phenomenon might be influenza vaccine policymakers paid more attention to HCWs in high-riskdepartments than in otherdepartments,⁸or the HCWs from high-riskdepartments realized that they had greater exposure to influenzaviruses.^10,14However, 29% of HCWs from high-riskdepartments remained unvaccinated, mainly because they were too busy. In the future, more measures need to be taken to promote influenza vaccination for this group.

In this study, 79% of HCWs showed a positive attitude toward influenza vaccination, and supported mandatory vaccination; 84% of HCWs said they agreed to compulsory influenza vaccination in workplace if they could be vaccinated for free. HCWs’ attitude toward vaccine effectiveness and safety and their experiences of witnessing side effects of vaccination, immunization failure and vaccine pathogenicity are associated with their influenza vaccinationbehavior.^13,14,20Therefore, future health education for HCWs should change their negative opinions and attitudes toward the influenza vaccine, promote them to recognize the risks of influenza scientifically, and enhance their confidence in influenza vaccination.

This study has limitations. Firstly, the survey can only represent the opinions of a certain percentage of HCWs and we do not know whether this part of the respondents are representative for overall HCWs in China. Secondly, 73% of respondents were HCWs from the defined high-riskdepartments who were more likely to receive the influenza vaccines, which may overestimate the influenza vaccination coverage. Thirdly, the vaccination status of HCWs in this study was self-reported,not based on the actual vaccination records of employees, and it may have recall bias. Finally, HCWs who saw the questionnaire link on WeChat may forward it to their colleagues, so it was difficult to calculate the response rate.

Disclosure of potential conflicts of interest

No potential conflicts of interest were disclosed.