Preoperative vaccination policy in patients vaccinated before surgery with a two-dose schedule in the context of anti-hepatitis B immunity status
Results of our previous study, conducted in 2009, showed that, even as there are no requirements or standard protocols for preoperative HBV immunisation in Poland, many surgeons still implement their own program: regarding elective procedures, 82% of surgical patients were vaccinated for HBV preoperatively, almost two thirds of whom were immunized at the request of referring surgeons; about one third of those vaccinated patients was immunized with a 2-dose vaccination schedule [
9]. Another study, conducted by us in 2013 among patients attending a primary care clinic, revealed that planned elective surgery was the main reason for their HBV immunization; similar rates were observed among adult patients from the Polish city of Katowice [
10,
11].
As planned elective surgery is the main reason for HBV vaccination regarding non-immunized adults and the preoperative immunization policy positively influences the HBV vaccination uptake in Poland, it should not be discontinued.
However, the results of the present survey reveal that this policy only partly fulfills its main goal - to reduce infections generated in health care facilities, since the regimen does not protect a significant fraction of patients against HBV infection. It refers especially to those vaccinated less than two months before surgery: overall almost one in two of all study participants who took two doses of HBV vaccine were found to present anti-HBs titer below protective level before operation, but almost two in three of those vaccinated 0–60 days before they were operated on.
Our findings are in line with the other studies [
16‐
19]; first of those were carried out in 1980s–1990s [
20‐
22]. As an example, 30% of infants, surveyed in 1984 in Senegal, and 11–27% of medical staff surveyed independently in Poland (1991) and Israel (1993) showed a lack of immune response to HBV vaccination after taking two doses of HBV vaccine [
20‐
22]. More recently, a lack of sero-positivity after two doses of HBV vaccine was found in 51% of adult Indian patients, in 11% of medical staff in Ceylon and in 8% of Chinese college students [
16‐
18]. Regardless of geographical region, time or population group surveyed, a significant proportion of vaccinated individuals showed a lack of protection against HBV infection after taking two doses of vaccine.
In our preliminary study on participants vaccinated before surgery, who took a 3-dose vaccination schedule, 88% presented protective levels of anti-HBs; significantly more than those who took only two doses [
19]. This is supported by others: protection was obtained in 86–99% of vaccinated individuals after taking a third dose of HBV vaccine [
16‐
18,
20‐
22].
According to the results of this study, it may be concluded that HBV immunization with a 2-dose schedule induces slow and weaker immunological response when compared with a 3-dose schedule. After taking two doses only, the highest percentage of protected patients was observed in the group operated on 60–180 days after immunization, not in the group operated on up to 60 days. The percentage of protected patients operated on over 180 days after immunization was similar to observed in the group operated on up to 60 days. Regarding the peak level of the anti-HBs after taking the third dose, Honorati et al. and found that it was reached 68 days after and remained stable for several years [
26]. Piratheepkumar et al. found that after two doses of vaccination, there was significant deterioration in protective immunity after four years. However, in individuals who received three doses - the protective immunity did not reduce significantly after four years [
18].
It has been shown that increasing age and male gender has an adverse effect on the outcome of HBV immunisation [
26‐
30]. What is noteworthy, the median age of our study participants was 52 years. Therefore, it might be expected that, in general, the immune response against HBV after vaccination with two doses in this group would be worse than in younger individuals, thus a significant proportion of them would not develop protection. In fact patients with an adequate response to HBV vaccination were significantly younger than those with an inadequate response. Furthermore, the population of patients referred for elective surgical procedures presented various co-morbidities. Although not observed in this study, possibly due to not enough numerous sub-groups of participants, some other studies have demonstrated patients in late stage kidney disease, with diabetes, chronic liver diseases and on immunotherapy are less likely to seroconvert [
30].
It may be assumed that for the majority of patients vaccination means protection, no matter the number of doses taken. One point of note is that none of the study participants who preoperatively took two doses of vaccine reported being informed of the mechanisms of HBV protection via vaccination, none were asked to check anti-HBs level 1–2 months after immunization. Although Polish surgeons widely recommend a preoperative HBV vaccination with at least two doses of vaccine - they do not routinely recommend the anti-HBs testing to check if a patient has been successfully immunized. In addition, test results are not required when admitting a patient for elective surgery. In the case of a healthcare-acquired HBV infection generated during a surgical procedure, on a patient immunized with two doses schedule, the hospital may claim the patient was in the “responders” group. Thus, it is impossible to verify an infection control error made by a facility. Patient HBV immunization, even with only two doses of vaccine, allows a hospital to avoid liability regarding any untoward acquisition of a nosocomial infection. For some cases, the fear of litigation related to a nosocomial infection could be a more potent stimulus for supporting preoperative HBV immunisation than any concern regarding patient protection in the acquisition of a nosocomial HBV infection [
9].
Additionally, a HBV immunisation certificate held by the patient would offer surgical staff a sense of security regarding patient-to-doctor HBV transmission. However, this also might be illusive and misleading. Data from the individual reports suggested that, in 2013, 22% of newly detected chronic hepatitis B cases in Poland received full vaccination against HBV and out of 1541 acute hepatitis B cases, six were fully vaccinated [
7].
There are many areas in
politics and
evidence that can influence a governmental decision or other group to adopt a certain policy. The modern concept of health policy involves
evidence-based policy (EBP) which relies on the use of science and rigorous studies to identify programs and practices capable of improving policy relevant outcomes [
31]. There are a number of methodologies for EBP, but one of the key characteristics is to separate uncertainties and control other influences outside the policy that may have an effect on the outcome [
32]. It seems that preoperative HBV vaccination obligation, in the case of elective surgery patients, in force in Poland between 1993 and 1997, was oriented more to surgical staff or hospital managers than patients.
Clearly, in the light of the results of this study, uncertainty regarding the benefits for patients of only taking a two-dose schedule, regarding protection from acquiring a nosocomial infection remains, and there is a certain amount of scepticism on whether other influences were thoroughly studied outside this vaccination policy that may have also had an effect on patients.
Limitations
The strong point of the current study is its pioneering character. Moreover, the study was conducted among patients from the randomly selected hospitals, therefore the study population may be a good representative of the whole region.
There are several limitations in our study. Firstly, the sample size was rather small which might influenced the observed associations or not reveal existing ones. Further studies on a bigger sample would be of value. Apart from studied variables, there might be some other cofactors for unsuccessful vaccine response, e.g. genetic factors [
30,
33,
34], which were not evaluated. Finally, considering a cross-sectional design, it was not possibile to rule out any cause-effect relationship between the factors assessed and vaccine response.