Barriers for vaccination of healthcare workers

ABSTRACT

Outbreaks of vaccine preventable diseases (VPDs) in hospital settings remain a challenge even in countries with established (childhood-) vaccination programs. Healthcare workers (HCWs) with an updated vaccination card play an important role in reducing the risk of nosocomial spread of VPDs. Yet, in many places, HCWs report their immunization status to be unknown or not updated. In times of a global pandemic, the debate on vaccination of HCWs is as hot as ever; do HCWs have an increased responsibility to get vaccinated against VPDs? If so, how do we increase vaccination uptake rates among HCWs? Mandatory vaccination against VPDs for HCWs has been introduced in some countries, but it may cause ethical dilemmas and not be culturally acceptable everywhere. We looked at vaccination policies and HCWs’ attitudes toward immunization against VPDs. We found that missing vaccine policies and lack of knowledge of VPDs, vaccination benefits, as well as inadequate organization around HCWs’ immunizations were important barriers to have a complete vaccination record. A systematic approach to employees providing information of VPDs and vaccinations, going through their vaccination cards and offering antibody testing where appropriate or a shot of a missing vaccine could support staff to adhere to vaccination schemes.

KEYWORDS:

• Vaccine hesitancy
• vaccine attitudes
• vaccine policy
• healthcare workers
• vaccine preventable diseases

Benefits of vaccination

Ensuring immunization of HCWs is important in order to avoid nosocomial spread of especially airborne VPDs such as measles, mumps, and rubella (MMR), pertussis, diphtheria, varicella and influenza.

Unvaccinated HCWs are more likely to be infected with VPDs; the risk of contracting measles for HCWs has been shown to be up to 19 times higher than for the general population.¹ Hence, unvaccinated HCWs pose an infectious risk to themselves, colleagues and especially vulnerable patients, and HCWs have indeed been identified as index persons in outbreaks of VPDs in hospital settings on numerous occasions.^2,3

This not only causes morbidity and mortality, but it is also costly to deal with nosocomial outbreaks of VPDs. An outbreak of measles among 10 HCWs in Hesse, Germany in 2017 was estimated to have an economic impact of 700.000 Euros.⁴ So, apart from reducing the negative human bodily impact, there are financial arguments on society level that also support vaccinating HCWs.^4,5

Missing vaccination policies and implementation strategies

In spite of heavy arguments supporting vaccination of HCWs, in numerous places including high-income countries, vaccination policies for HCWs are insufficient,⁶ and many HCWs do not have a complete immunization card or are unaware of their immunization status. This was illustrated in data published by our group last year showing that in two selected hospitals in Denmark, 20–30% of HCWs were unsure of or denied being immune to MMR defined as previous infection or vaccination. Twelve percent and 44% of the HCWs were unsure of or denied previous vaccine or infection with varicella and pertussis respectively. Sixty-one percent did not receive the influenza vaccine in the previous winter season.⁷

Similar findings of variable levels of self-reported immunity to VPDs among HCWs have been demonstrated in numerous other studies.^1,8–11

Despite most countries having well-established childhood vaccination programs, a large variability exists in policies regarding vaccination of HCWs. In some countries there are hardly any policies in place at all, e.g., in Denmark, whereas in, for example, Albania vaccination against MMR is mandatory for HCWs to get hired.⁶

In the USA, 15 states have introduced mandatory MMR vaccination for hospital HCWs.¹² However, only few regulations include penalties for noncompliance,¹ hence they are more appropriately regarded as recommendations. In Australia, proof of immunization against MMR, pertussis, influenza, hepatitis B and varicella is recommended at a national level (without specification of penalties for noncompliance).¹³

The above illustrates that there is no consensus between or even within countries on vaccination policies for HCWs, and that there is discrepancy between desired levels of immunization and actual immunity against VPDs among HCWs.

The World Health Organization (WHO) recommends that each country creates guidelines for HCWs adapted to the country’s burden of disease.¹⁴ Adding to this we may stress the importance of making specific recommendations for each disease/vaccination adapted to the age of the HCW, area of duty, previous history of immunization, cutoff levels for antibodies, etc., and provide vaccinations free of charge for HCWs. Each country should preferably set out national targets for vaccination uptake rates for HCWs and monitor the progress of reaching this threshold. A proper detailed log-frame is crucial to successful implementation of a vaccine policy.

Vaccine hesitancy

Apart from missing vaccine policies and guidelines for implementation, noncompliance of HCWs contributes to the insufficient vaccine uptake levels of HCWs.

The WHO’s Strategic Advisory Group of Experts on Immunization (SAGE) have defined three behaviors of vaccine hesitancy among HCWs, namely issues of

• confidence (i.e., level of trust in a vaccine (effectiveness/safety) or provider (reliability and competence of health services + motivation of policymakers who decide to introduce the vaccine)).

• complacency (improper perception of own susceptibility to contracting the disease and ability to spread it, risk of disease neglected).

• convenience (issues of access).

Vaccine hesitancy among HCWs may depend on the vaccine being in question, and the nationality and characteristics of the subgroup of HCWs asked. Hagemeister et al. showed that pediatric HCWs were more likely to be vaccinated than surgeons.¹⁵ Other studies showed that vaccine hesitancy may depend on profession, age, knowledge of side effects, etc.^7,16 Most studies on vaccine attitudes of HCWs are based on the influenza vaccine.

Our study was carried out in a pediatric setting in Denmark in 2019.⁷ It illustrated that complacency was an important reason for influenza vaccine refusal, as 22% of refusers stated that they had refused because they were “rarely sick” and 15% because they regarded the vaccine as “not necessary.” The majority of these refusers were nurses or non-clinical staff. Twenty percent of the study population had a confidence issue being concerned with side effects or not wanting it for other reasons. The remainder of the influenza vaccine refusers had convenience issues such as they “forgot/were too busy” to get the shot (15% – physicians accounting for a large proportion of this sub-group) or they were not offered the vaccine (6%). Fourteen percent had “another reason” not to get vaccinated including lack of practical information on where to get the shot, being away on maternity leave or sick day, etc. Not all vaccine refusers gave a reason.

Likewise, Pinto et al. performed a study in Italy in 2018 looking at influenza vaccine uptake rates and vaccine hesitancy among HCWs. The group found that only 56% of doctors, 19% of nurses and 27% of other personnel had accepted the influenza vaccine that year. Reasons to decline vaccination were related partly to complacency, as 7% (doctors) – 27% (other personnel) deemed the risk of transmitting the disease to patients as low, and 11% (doctors) – 29% (nurses) thought that the risk of contracting influenza virus was low.¹⁷

Seventy-three percent (nurses) – 91% (doctors) generally believed that the “risk of severe damage from vaccination” was low. Interestingly, 26% (doctors) – 36% (nurses) in the Pinto cohort found vaccine information to be insufficient.¹⁷

Hagemeister et al. describe issues of complacency to be a main driver of vaccine hesitancy among HCWs.¹⁵

Same overall categories of reasons to decline influenza vaccination has been found by other colleagues, e.g., Feemster et al. in a pediatric tertiary care hospital in the US in 2010¹⁸ and by Karnaki et al. in a survey among HCWs in 14 European countries in 2019.¹⁶

Several studies reveal that the most important motivating factor for HCWs to receive the influenza vaccine was protection of themselves and patients.^7,19,20 Hulo et al. found that vaccinated HCWs had higher knowledge scores on influenza and vaccination against influenza compared to unvaccinated HCWs.²⁰

Mandatory vaccination?

In the debate of HCWs’ compliance to vaccination policies, the suggestion of mandatory vaccination with penalties for noncompliance has been put forward and in some places effectuated.⁶ Penalties may include being asked to fill out a declination form, mandatory use of face mask, reduced patient contact, end of contract – or vaccination may simply be mandatory prior to employment etc.^6,21

Arguments in favor of this strategy point out the increased responsibility of HCWs to be fully vaccinated, as they provide care to vulnerable patients and should not be an additional risk for the patient seeking medical help. On top of the consequences for the patients, which could be fatal, a nosocomial outbreak of a VPD originating from a HCW could have juridical implications.²² Hence, people in favor of mandatory vaccination of HCWs argue that the societal responsibility overrules the rights of the individual HCW.¹⁸

HCWs’ own support of mandatory vaccination depends considerably on the vaccine in question. In a study performed by Maltezou et al. in Greece in 2012, 71% of HCWs supported mandatory vaccination of staff, however this covered a considerable range from 13% supporting mandatory vaccination against mumps up to 78% supportive of mandatory influenza vaccination.²³

Contrary to this, the cohort in Linstow et al. were more supportive of mandatory vaccination against MMR compared to influenza. Interestingly, only 56% of HCWs in favor of mandatory vaccination against influenza received the vaccination themselves in 2018/2019.⁷ This shows that lack of vaccination coverage may not only be due to an act of will against vaccination but rather depend on, for example, convenience factors. This statement is supported by Taddei et al. who found that one of the main reasons for the relatively low vaccine coverage of HCWs was indeed lack of active offer of vaccines.²⁴

In the Linstow cohort, 13–21% of HCWs were in doubt whether vaccination should be mandatory, but the majority (91.4–95.3% depending on which vaccine) thought vaccines should at least be offered to HCWs at the work place.⁷

A survey among 964 hospitals randomly selected across the US showed that vaccination uptake rates among HCWs at hospitals with mandatory influenza vaccination policies (with penalties including replacement of area of duty, termination of contract and unpaid leave) were almost double as high compared to hospitals without mandatory vaccination policies.²⁵

However, while mandatory vaccination may be effective under some circumstances, it does cause ethical dilemmas and in some countries it may not be culturally accepted.

Furthermore, the question is whether mandatory vaccination of HCWs is even necessary? Where the US has managed to attain 95% coverage rates of measles vaccination in the general population by mandatory vaccination, the Netherlands and Sweden reached almost same levels (90–93%) based on a voluntary approach.²²

For HCWs, it may be hypothesized that a coercive vaccination strategy could cause a reduction in trust in health authorities in some cultures. This would imply that even if HCWs did comply to a mandatory vaccination policy, their trust in and support of health authorities might get impaired to a certain extent. If so, one may ask what the impact of this could be?

A multi-component approach

Based on our findings, it seems that only a smaller proportion of vaccine hesitancy is due to confidence issues (approximately 20%). A large part of vaccine hesitancy among HCWs is based on issues of complacency and convenience – both of which can be addressed with other methods than top-down pressure in the form of mandatory vaccination. Even confidence issues may be addressed by a voluntary approach.

This was supported by Karnaki et al. who made the paradox finding that even if the majority of HCWs in 14 European countries self-reported low levels of compliance regarding most immunizations recommended for adults in Europe, the majority (87%) had positive attitudes toward vaccines.¹⁶ This finding supports that lack of will to receive vaccines is not a main driver for the low level of compliance, thus forcing HCWs is most likely unnecessary.

Hence, a combined strategy including education of HCWs and improved organization of vaccination could be a rational approach in order to increase vaccine uptake rates in HCWs.

Not many studies have evaluated the effectiveness of motivational interventions to increase vaccine coverage in HCWs. In New South Wales in Australia, a vaccination policy was implemented in 2008–2009. Even if mandatory, the approach involved education of staff, listening to their concerns, communication of the evidence supporting the policy, and addressing logistical challenges. The implementation was met with a high level of support from HCWs and no resistance to implementation by organized labor.²⁶ This stands in contrast to similar attempts of introducing mandatory vaccination policies in the US and Canada, which resulted in pronounced resistance and the policy being pulled back.²⁶ Even if the Australian policy was mandatory, the study does underline how motivational factors are crucial in order for a policy to be successful.

Jarret et al. conducted a systematic review in 2015 on strategies addressing vaccine hesitancy and found that the most effective strategies were “multi-component based” including dialogue-based interventions (raising knowledge and awareness), reminder-recall approaches and incentives.²⁷ This study was not aimed at HCWs but focused on vaccine hesitancy in general. However, the results could be used as a source of inspiration, since – as demonstrated above – vaccine hesitancy among HCWs also is multifactorial, and a successful approach may need to be multi-facetted.

Given the complex nature of vaccine hesitancy among HCWs, we suggest first step to be analyzing the main barriers for vaccination in a target population. This could be done at country-level but even at hospital- or ward level depending on the extent of noncompliance among HCWs locally. E.g. in a ward showing nurses being more likely to refuse vaccination due to complacency issues and doctors due to convenience issues, targeted interventions to each subgroup of HCWs might be beneficial.

We hypothesize that analyzing context-specific barriers to vaccination for each vaccine and systematically addressing these barriers in an organized, multicomponent approach would increase vaccine uptake levels among HCWs.

Approaches would need to include (1) national vaccination policies, (2) easy-to-follow flowcharts for a straight-forward implementation of policies, (3) education of HCWs and (4) easier access to free vaccinations.

Disclosure of potential conflicts of interest

No potential conflicts of interest were disclosed.

Additional information

Funding

No funding was needed for publishing this article.