Health care workers in Pearl River Delta Area of China are not vaccinated adequately against hepatitis B: a retrospective cohort study

The present study demonstrated that HCWs in southern China, overall, had a disappointingly
low rate of HBV vaccination (near 40 %). Furthermore, approximately one-fifth of vaccinated
HCWs lacked serological evidence of protection. Vaccination rates differed in relation
to HCWs’ department of employment and profession.

HBV can be transmitted by blood transfusion, injection 16], operation, dental treatment 12], needle stick injuries, and mother-to-child vertical transmission. Estimates of the
rate of HBV infection of HCWs following a one-time needle prick with an HBV-exposed
needle range widely from 6 to 30 % 3]. HCWs work long hours in high-demand environments and are exposed frequently to patients’
bodily fluids, including blood, secretions, and excretions. The potential risk of
acquiring blood-borne viruses through needle stick injuries has led several authors
to examine the prevention of such incidents 13], 17]. Many reports have indicated that the main and, probably, only effective mechanism
of preventing HBV infection among HCWs is an effective vaccine, which has been in
use for about two decades 18], 19]. In 1991, the World Health Organization recommended that all countries should implement
an anti-HBV vaccine in their national vaccination program by 1997 20], 21]. Given HCWs elevated risk of HBV infection, and the related risks of infected HCWs
transmitting the virus to uninfected patients, the strength of occupational protection
of HCWs by vaccination should be increased aggressively 22].

The HBsAg positive rate found for HCWs in Pearl River Delta Area of southern China in this study was lower than expected 23]. However HCWs working in infectious diseases departments and technicians were at
particularly likely to have been infected with HBV. Some portion of people who receive
HBV vaccine inoculation remain at risk of HBV infection. Prior work suggests that
HBV vaccination efficacy is better in younger recipients 24]. Eight vaccinated HCWs in the present study were HBsAg-positive, indicating that
they were harboring an active HBV infection despite having been inoculated; presumably,
they did not produce sufficient (or any) protective antibodies in response to the
vaccine. Hence, serum anti-HBs levels should be assayed postvaccination to confirm
whether protection has been conferred. The presence of protective antibodies in some
non-vaccinated HCWs was presumably due to prior natural exposure to the virus. Nevertheless,
HCWs in the vaccinated group were less likely to have a current HBV infection (indicated
by HBsAg positivity) than HCWs in the non-vaccinated group, indicating that HBV vaccination
had been clinically meaningful, though it was not 100 % effective.

Interestingly, the rate of workers having serologically evident protection by natural
infection versus vaccination was not uniform across departments. HCWs in the infectious
diseases department had the highest rate of antibody produced by natural infection;
indeed more HCWs working in infectious diseases departments were infected with HBV
naturally than were vaccinated. It is expected that HCWs who work in infectious diseases
departments, and thus work directly with hepatitis-infected patients and samples,
have a high risk of HBV exposure. Hence, the low rates of vaccination among these
HCWs indicate strongly that there is a need for greater awareness of transmission
risk and for promotion of HCW vaccination.

The relatively higher rate of vaccination among ob/gyn HCWs observed in this study
could be related to these HCWs having gained greater awareness of the HBV vaccine
as a consequence of their involvement with infant immunization plans. The four HCWs
working in hemodialysis departments (encompassed in “Other” in Table 2), an area of particularly high infection risk 23], were noteworthy for characteristically obtaining anti-HBs by way of vaccination,
indicating that they have a particularly high awareness of their occupational need
for protection. It is noteworthy that immunity source also differed in relation to
profession. Technicians with anti-HBs antibodies obtained immunity mostly through
natural infection, whereas medical doctors with anti-HBs antibodies obtained immunity
more often through vaccination. The low vaccination protection rate of technicians
is particularly concerning given their frequent exposure to patients’ bodily fluids
25].

It is our view that HCWs who have a reasonable expectation of being exposed to blood
on the job should be offered the HBV vaccine as a matter of course. Furthermore, HCWs
should be informed that vaccination is not always effective and serological testing
should be performed to confirm vaccine effectiveness. HCWs should be counseled regarding
what steps they should take to protect their health in cases of vaccine non-responsiveness.

This study has the limitation of being largely limited to enrollment of HCWs in Pearl River Delta Area of southern China. So the HCWs enrolled in the present study can represent Local
area of the HCWs in the Pearl River Delta Area of China to a certain extent. This geographical limitation limits the generalizability
of these findings. Additional studies involving HCWs in other regions are needed to
determine whether the patterns of data observed here are common southern China, throughout
China and Asia at large, and larger retrospective studies are needed to confirm the
present results. There ere also the limitation of the publication delay due to the
delay in preparing the manuscript and the submission.