Understanding Vaccination Hesitation among Health Professionals: A Systematic Review of Qualitative Studies

"[H]ealthcare professionals (HCPs)...are the cornerstone of vaccination as they can move undecided populations not only towards vaccination but also towards non-vaccination."

Healthcare professionals (HCPs) are a group for whom the uptake of vaccines is of particular importance, mainly for three reasons: (i) for their relevant role in building or breaking trust between their patients and vaccination programmes, as they are the most trusted source of information and guidance; (ii) owing to the refusal on unvaccinated HCPs to provide vaccine counselling and deliver vaccines to patients; and (iii) due to their greater capacity for workplace-associated infection and transmission. The aim of this systematic review was to explore the knowledge, beliefs, attitudes, and barriers associated with HCPs' own vaccination and their vaccine recommendations to patients.

A systematic review of studies published from January 1 2000 to June 1 2020 was conducted by searching PubMed and EMBASE electronic databases for relevant papers published in Portuguese, English, or Spanish. From a total of 2,916 studies identified, 36 articles met the inclusion criteria. Regarding the study population, 22 studies included nurses, 24 comprised doctors, four included pharmacists, three reached midwives, and one study involved clinical officers.

Some of the factors cited by HCPs in the studies that may contribute to vaccine hesitancy were: (a) concerns regarding safety or efficacy of vaccines (23 articles); (b) time constraints (21 articles); (c) lack of knowledge about the vaccination/vaccine (19 articles); (d) costs (13 articles); (e) distrust of pharmaceutical industry (8 articles); and (f) other - e.g., considering oneself insusceptible (7 articles), stock shortage (7 articles), lack of personnel (5 articles), and feelings of unnecessary vaccination (5 articles).

Seven articles presented information about social influences that condition HCPs. In more detail, the media influenced the participants in three studies, their peers in four, and family and friends in one. For instance, it was shown that the refusal of vaccines by other providers has impacted HCPs' vaccination practices. Other barriers identified were those related to shifting the responsibility for vaccination to others, such as the feeling that it is not their (HCPs') job or forget to advise patients to get vaccinated. In some studies, past experiences were related to HCPs' decision to vaccinate (or not).

Eleven articles mentioned the role in vaccination that HCPs perceive as belonging to them. Six articles highlighted the role of these professionals as educators by providing information and resolving concerns. In two of the six articles, the belief of professionals of it being their responsibility to advocate and suggest vaccination is presented, while in two articles, some of the HCPs stated they should respect patients' autonomy by providing correct information objectively to allow them to make an informed decision.

The resource that HCPs used as the source of information was described in 8 articles, and in these, (i) in four, HCPs used media sources or the internet to obtain information about vaccines; (ii) in four, they used only scientific sources; (iii) in three, participants' decisions were based on official recommendations; (iv) in two, they relied on peers; (v) in one, participants referred to using basic search practices; and (vi) in other articles, none of the participants searched for information.

All the articles included in the present systematic review cited a range of HCP beliefs towards vaccination. The review detected doubts about the benefits of vaccines, revealing a need for training and information on vaccination, which health professionals themselves perceived as necessary.

Based on the results, the researchers propose a new approach to systematising HCPs' vaccination behaviour through the application of a mixed model of intrinsic and extrinsic factors. Such a model (see Figure 2 in the paper) allows one to hierarchise the conditioning factors of hesitancy, which have been divided and classified into knowledge/sources of information, belief, attitudes, and practices, aiming to explain the final behaviour regarding their own vaccination or recommendation to patients.

Applying this approach to the findings allows for an understanding of, for example:

• The fact that knowledge gaps are the most-cited intrinsic factor in the articles included - This lack of knowledge not only concers vaccines but also about the diseases they prevent. The researchers point to the sources of information used by HCPs, which reveal that news media utilisation increases vaccine refusal, whereas access to scientific literature was related to the likelihood of accepting vaccines.
• The role of the HCP-patient relationship and its educational role in bridging  knowledge gaps and modifying erroneous patient attitudes (such as anti-vaccine attitude due to limitations in available knowledge, negative effects of media, distrust, and concerns about side effects) - This finding highlights the need to provide patient communication tools, which is confirmed by HCPs themselves acknowledging as potentially helpful in increasing patient confidence in the HCP.
• The fact that HCPs perceive they are not susceptible to vaccine-preventable diseases - This finding is compounded by the belief that some health professionals do not consider their patients to belong to the relevant group(s) for vaccination. This may be of great relevance from a public health point of view since the first belief would be associated with a lower self-vaccination and the second belief with a lower recommendation to patients, which increases the likelihood that the medical office is a source of infection.
• The finding that extrinsic factors have a major influence on HCPs' vaccination and recommendation - For example, lack of time during the consultation has a negative effect on the decision of vaccination or recommendation, and the presence of other clinical priorities or concerns was frequently cited as barriers to vaccination. Also, costs and fees of vaccines were an important factor limiting vaccination, and HCPs' perception of limitations in access to available knowledge due lack of clear guidelines is seen as a frequent drawback.

In conclusion, this review "suggests that interventions to combat vaccine hesitancy should increase HCP education on vaccine efficacy and safety, as well as intervene on health system factors such as cost and time per visit. In this way, we could tackle the problem of vaccine hesitancy, which seriously threatens global public health."