Охват вакцинацией против гепатита В работников здравоохранения Монголии
Работники здравоохранения подвергаются высокому риску профессионального заражения, поэтому профилактика инфицирования вирусом гепатита В (ВГВ) является важной проблемой гигиены труда. Ежегодно доля работников здравоохранения, подвергающихся воздействию ВГВ, во всем мире составляет 5,9%, что соответствует примерно 66 000 предотвратимых за счет вакцинации случаев инфицирования ВГВ.
Цель исследования - анализ охвата вакцинацией против ВГВ работников здравоохранения.
Материал и методы. Проведено кросс-секционное исследование методом случайной выборки среди работников здравоохранения. Данные были собраны с помощью разработанной структурированной анкеты и проанализированы с использованием SPSS версии 21.
Результаты. Исследовательская группа опросила 1135 участников об их статусе вакцинации, из них 883 (77,8%) были вакцинированы, а 199 (17,5%) не вакцинированы. Среди вакцинированных медиков 3 дозы вакцины против ВГВ получили 538 (60,9%), 2 дозы вакцины - 257 (29,1%), 1 дозу вакцины - 88 (10%). Из числа работников здравоохранения, родившихся до 1992 г., 931 (49,8%) получили 3 дозы вакцины, в то время как 19,8% не были вакцинированы. Среди 204 медиков, родившихся после 1992 г., 33,3% не были вакцинированы, в то время как 36,3% получили полный курс вакцинации против ВГВ.
Заключение. Половина медицинских работников, родившихся до 1992 г., получили 3 дозы вакцины, в то же время только 1/3 медицинских работников, родившихся после 1992 г., были полностью вакцинированы. Таким образом, необходима активизация внедрения программ вакцинации против ВГВ на всех уровнях оказания медицинской помощи.
Ключевые слова:медицинские работники; гепатит В; вакцина против гепатита В; Монголия
Финансирование. Исследование не имело спонсорской поддержки.
Конфликт интересов. Авторы заявляют об отсутствии конфликта интересов.
Благодарность. Авторы выражают искреннюю признательность всем людям, которые оказали поддержку в период проведения опроса, и особую благодарность участникам опроса, поставщикам медицинских услуг и менеджерам здравоохранения, а также Монгольскому национальному университету медицинских наук, Монгольской академии медицинских наук, Национальному центру инфекционных заболеваний, а также Азиатскому банку развития и Всемирной организации здравоохранения за финансовую поддержку и техническую помощь.
Для цитирования: Нямсурэн Н., Алтангэрэл Э., Бямба Т., Ганболд С., Аюш Э.-А., Нямдаваа К., Баатархуу О. Охват вакцинацией против гепатита В работников здравоохранения Монголии // Инфекционные болезни: новости, мнения, обучение. 2023. Т. 12, № 3. С. 88-95. DOI: https://doi.org/10.33029/2305-3496-2023-12-3-88-95 (англ.)
Human resource is the backbone of the healthcare system, and the healthcare workers should be protected and prevented against occupation-related infections, including hepatitis B. It is one of the most common blood-borne infections which cause liver-related complications, including cirrhosis and hepatocellular carcinoma. Statistics show that 1.5 million new infections occur annually and there are more than 296 million people live with chronic hepatitis B infection worldwide [1, 2]. Fortunately, it can be protected by a vaccine, which can prevent infection and related liver complications and death. Therefore, healthcare workers must be vaccinated to avoid exposure to the infection while providing routine healthcare services contacting blood and other body fluids. According to the CDC (The Centers for Disease Control and Prevention) recommendation, the fully vaccinated healthcare workers will be protected by more than 90% after the third dose in adults aged ≤40 years [3-5].
Since healthcare workers are at high risk of occupational exposure, hepatitis B virus infection is a challenging occupational health problem . The annual estimated proportion of healthcare workers (HCWs) exposed to hepatitis B virus (HBV) globally is 5.9%, corresponding to an estimated 66 000 preventable HBV infections each year among HCWs worldwide . The World Health Organization (WHO) global hepatitis strategy, endorsed by all 194 WHO the Member States, aims to reduce new hepatitis infections by 90%, prevalence of hepatitis B virus infection by 95%, prevalence of hepatitis C virus by 80% and deaths by 65% between 2016 and 2030. This strategy is reflected in the national hepatitis prevention plans of some countries, which are in the process of reaching their targets [5-7]. Member countries of WHO and the Western Pacific and Asia Region (WPRO) are working on three key policy documents to curb the spread of viral hepatitis by 2030: Global health sector strategy on viral hepatitis 2016-2021; Regional Action Plan for Viral Hepatitis in the Western Pacific 2016-2021; and Regional framework for the triple elimination of mother-to-child transmission of human immunodeficiency virus (HIV), hepatitis B and syphilis in Asia and the Pacific, 2018-2030 . Measures and national programs against viral hepatitis vary from country to country, depending on the specifics of the countries and morbidity patterns.
The survey (2017) covered 135 (70%) of the 194 WHO member countries, which is 87% of the world’s infected population, and asked whether countries had national policies, programs, and plans, funding, civil society organizations, diagnosis, treatment guidelines, access to treatment, and strategy to combat hepatitis. 84 (62%) of the participating countries had developed a national program, of which 49 (58%) had dedicated funding, and 62 (46%) had engaged with civil society organizations; those involved with civil society were more likely to have a funded plan than others (52% vs 23%, p=0.001). Guidance on testing pregnant women (for HBV) and people who inject drugs [for hepatitis C virus (HCV)] was available in 70% and 46% of Member states, respectively. And 59% and 38% of Member States reported universal access to optimal therapies for HBV and HCV, respectively .
Mongolia is one of the countries of the WHO, WPRO, where 116 million people are chronically infected by hepatitis B. In the last ten years, the prevalence of HBV among the relatively healthy population of the country has decreased from 11.8 to 10.6%, and the majority among the relatively healthy population of Ulaanbaatar has reduced from 9.3 to 9.0%, respectively .
The Government of Mongolia has taken several measures to reduce the prevalence of hepatitis infection among the population. As a result of these measures, the population’s incidence and mortality of viral hepatitis have dropped dramatically. Resolution No. 478 of Ministerial Council of People’s Republic of Mongolia on combating viral hepatitis in 1972 was a policy document that considered viral hepatitis separately from other infectious diseases (Fig. 1). In Mongolia, the prevention of viral hepatitis is aimed to (1) improving immunity against the hepatitis B and A viruses and (2) improving the control and prevention of infection in health care facilities. The following key interventions have been implemented in Mongolia to reduce the spread of HBV infection:
· Since 1992, newborns have been vaccinated against HBV.
· Immunization coverage within the first 24 hours for newborns was 97.6% in 2013.
· In 2012, the Ministry of Health and Sports determined to vaccinate HCWs for 2 doses of hepatitis B vaccine, and the immunization coverage among HCWs reached up to 58% in October 2014, with a further increase of 80% by January 2015.
· In 2017, Mongolia started implementing Healthy Liver Mongolia National Program within the framework of the regional goal. However, there is a need to improve policy and regulations to prevent HCWs from occupational exposure to hepatitis infection.
In recent years, the number of people working in the health sector in Mongolia has been increasing. As of 2018, there are 52 274 employees, of which 10.5 thousand doctors, 11.9 thousand nurses, 963 feldshers, 1129 technicians, and 2526 bag feldshers work in 4005 public and private health organizations .
There is limited evidence on vaccination coverage of HBV among health care workers in Mongolia. The few available data was based on the study, which covered a few hospitals rather than nationwide. Lack of evidence-based information makes it difficult to plan for a realistic and practical policy for the protection of HCWs. Consequently, there is a lack of research on HBV immunization among the public and private health care providers to suggest to policymakers the status, challenges, and opportunities for improving the safe working condition of HCWs.
Therefore, the objective of this study was to find out the hepatitis B vaccination coverage and the associated factors among HCWs in the country.
Material and methods
Sampling and study participants
A cross-sectional study was conducted from April 2019 to March 2020 to assess vaccination coverage among HCWs. As of 2019, 54 687  HCWs are working in the health sector. In determining the scope of the study, the results of HBV vaccination of HCWs were estimated to be statistically representative of national, regional, and organizational levels. Therefore, the study team used a multi-stage sampling to ensure for inclusion of the study population from all geographical and socio-economic regions of the country. In order to evenly cover the different geographical and socio-economic regions of the country, the study areas were randomly selected from 4 regions (central, western, eastern, and khangai) of the country. The selected areas are Ulaanbaatar and Orkhon province as urban areas and 4 provinces namely Arkhangai, Govi-Altai, Dornod, Umnugobi as rural areas.
The type and level of healthcare facilities in Mongolia are considered during the selection of the study participants. Medical professionals  and medical staff  were selected for the study. When determining the sample size the percentage of hepatitis B surface antigen (HbsAg) of the target group was considered as 50.0% with a probability of 95% (Z=1.96), standard deviation (p=0.05), complex sample impact coefficient. The minimum required sample size for the study was calculated with a 10% nonresponse rate. A total of 1200 doctors and medical staff were estimated to be involved in the study as a sample size.
The study participants were selected using a simple random sampling method and the sampling frame comprised a list of health care workers obtained from the human resource department of selected health care facilities. HCWs who were present at work during the study period were considered for the study and the main inclusion and exclusion criteria were used by the study team.
Questionnaire and data collection
A standardized self-administered questionnaire was used by the study team to collect information concerning HCWs’ demographic characteristics and HBV vaccination status. The questionnaire covered the information on socio-demographics age, sex, years of service, occupation, education level; occupational department, unit, type of work, years of service in the organization; HBV vaccination statuses, such as postpartum immunization and catch-up immunization; the reason of partial vaccination or not vaccinating.
To ensure the quality of the data, questionnaires were piloted, reviewed, and checked for any errors, omissions, inaccuracies, or ambiguities and non-compliant questionnaires were returned to the researchers for correction and accepted if they met the requirements. The study involved 1135 health care workers working in all departments including medical doctors, nurses, clinicians - both surgical and medical-related specialties and laboratory technicians and other staffs from primary and referral level 36 health care facilities in 2 urban and 4 rural provinces of Mongolia.
Statistical data analysis
The data is entered into a study database, which is re-checked for any error after entry. If any errors occurred, the original digital data sheet was checked again, and the information was sorted out. Statistical analysis of the study data was performed using SPSS-21 software. The results are expressed as a percentage and mean of the knowledge and attitudes of the study population. Estimates (prevalence) and the difference between groups were calculated using 95% confidence intervals. The sampling errors that may affect the accuracy of the results of the study population were measured by the measured variables and the standard error of the results. Also, when calculating the data distribution using the Kolmogorov-Smirnov test, most of the numbers were unevenly distributed, so the relevant non-parametric criteria, such as the Mann-Whitney U test and the Kruskal-Wallis test, were used to calculate the mean and differences between groups. The Chi-square test was used for statistical analyses for categorical variables.
The research ethics approval was given after it was discussed at the meeting of the Medical Ethics Monitoring Committee of the Ministry of Health on June 24, 2019 and the written consent forms were obtained from all subjects’ prior questionnaire.
HBV vaccination status among HCWs
The demographic situation of the participants is described in Table 1. Most of the study population were women (86.1%). In terms of educational level, participants with university-level education were predominant and made up 51.9% (589) while 36.2% (411) were with college and high school education. In regard to/regarding marital status, 77.1% (875) were married. The majority of participants (82.0%) were born before 1992 or prior to initiation of vaccination against HBV in Mongolia. The median age of the participants was 38 years and the participants’ median employment year in the health sector was 7 years. 60.6% (688) of them have been working in the health sector for up to 10 years. According to the type of health care facilities, 35.2% (399) of participants were from referral level health care facilities, which is similar to the national data on the distribution of health workforce according to the level of health care facilities. And 42.3% (480) are from 4 province general hospitals, Regional Diagnostic and Treatment Centers (RDTC) and Chingeltei district general hospitals, 11.9% (135) from family and soum health centers, and 10.7% (121) from private hospitals.
HCWs included physicians, nurses, and other clinical (nursing assistants, obstetricians, midwives, laboratory technicians) and non-clinical workers (clerical, laundry, administrative, and other staff). Most of the participants were nurses (28.0%), medical doctors (29.1%), and 13.5% (153) were service staff. Midwives, laboratory assistants, dental technicians, etc. accounted for 24.3% of the total study participants. In terms of location, 753 HCWs from urban areas and 382 were rural provinces.
Based on the classification of jobs and exposure risk level , the study team categorized the participants into the following 3 risk groups in terms of exposure to HBV infection. Of the total survey respondents, 38.9% (442) worked in high-risk jobs for HBV exposure, 31.9% (362) worked in medium-risk jobs, and 29.2% (331) worked in low-risk jobs. Of the physicians, 12.2% (138) of the respondents were surgeons, 10.7% (121) were obstetricians, and 42.6% (484) were specialists in infectious diseases, resuscitation, and trauma departments.
The study team interviewed all 1135 participants about their vaccination status and 77.8% (883) of them said that they have received HBV vaccination while 17.5% (199) of the participants reported that they’re not vaccinated. Table 2 describes the vaccination status of the study participants including the number of vaccination doses. Among 883 HCWs who reported that they are vaccinated, 47.4% (538) of them received the full 3 doses of HBV vaccine while 22.6% (257) were received 2 doses of vaccine and 7.8% (88) were received 1 dose of vaccine. In terms of vaccination coverage, nurses (168) and physicians (160) were vaccinated more than in other occupations. Among unvaccinated HCWs, other HCWs such as clerical and laundry staff, nurses, and physicians were dominated.
Out of 931 HCWs who were born before 1992, 49.8% of them had completed three doses of the vaccine while 19.8% had not been vaccinated at all. However, 33.3% of 204 HCWs who were born after 1992 were not vaccinated (Fig. 2) while 36.3% of them received full doses of the HBV vaccine (χ2=28.52, p<0.001).
The average dose of HBV vaccine administered by all HCWs was reported as 1.95±1.20, and the highest dose by type of hospital was 2.27±1.07 in HCWs of soum and family health centers. The dose of HBV vaccine administered by private HCWs (Fig. 3) was 1.25±1.17 (p<0.001). In terms of the level of health care facilities, six out of ten staff at the Soum and Family Health Center and one out of every two staff at the referral health care facilities reported that they had received three doses of HBV vaccine (χ2=78.28, p<0.001).
Analysis of participants’ vaccination coverage according to occupational risk for HBV infection revealed that there is similar vaccination coverage among HCWs for high and low-risk groups. Although vaccination coverage was the highest in the medium-risk group there was no statistically significant difference among the groups (χ2=2.96, p=0.228). The study team investigated how HCWs were vaccinated, and the result showed that 40.4% of the participants were vaccinated at the workplace while 30.8% were vaccinated voluntarily and 5.46% were vaccinated due to employment requirements. The study result shows that voluntary vaccination status was high among men 57 (36.1%), among people born before 1992 292 (31.4%), among those working in referral hospitals 318 (36.2%), and among people with 11-15 years’ employment in the health sector 38 (33.9%). The percentage of participants who were vaccinated at the workplace was high among women [400 (40.9%)], among people born before 1992 360 (38.7%), among HCWs from referral level health care facilities 353 (40.2%), and among HCWs with less than 5 years of employment in the health sector 214 (46.2%).
Reported reason for partial vaccination and not vaccinated
Further, the study team looked at the reasons for partial vaccination and for not vaccinating. The most mentioned reasons for partial vaccination were being busy (23.0%), didn’t know that 3 doses should be administered (15.5%), and no one warned about full vaccination is needed (12.1%), forgetting to get vaccinated (13.0%). Out of partially vaccinated people, 1.3 % said, they knew their immune status due to their immunity test on HBV (Fig. 4).
The reasons for partial vaccination were analyzed according to participants’ demographic variables. There were 345 HCWs, who had partial vaccination doses (1 and 2) and only the responses from 288 of them were valid for data analysis. The following groups of the people were the most among the partially vaccinated ones, which are: women, higher educated participants, and people at 20-49 years old, physicians, and HCWs from referral health care facilities.
The main reason for not getting vaccination is the busy schedule (35.9%) among the 178 valid responses from 199 un-vaccinated people. Many of them were women, nurses, aged 20-29, with less than 5 years of working experience and were from the referral level hospitals (Table 2).
We randomly selected 1,135 HCWs from 36 healthcare facilities. Thus, 86.1% of the participants are women, 51.9% have a bachelor’s degree, and 77.1% are married. Most of them, or 82%, were born in Mongolia before 1992, 24 hours after the start of HBV vaccination in Mongolia. The median age of the participants was 38±18 years and the median number of years working in the hospital was 7±16 years. 38.9% (442) of the participants work in high-risk jobs for HBV exposure, 31.9% (362) work in medium-risk jobs, and 29.2% (331) work in low-risk jobs.
For healthcare workers, the risk of infection is an accidental injury to the skin or mucous membranes by needles or other sharp instruments contaminated with infected blood. The risk of infection among the healthcare workers have been estimated for HBV, HCV, and HIV infection as 37.6%, 39%, and 4.4%, respectively . Moreover, a person who has not been vaccinated against HBV has a 6-30% risk of infection if he or she is exposed to an HBV-infected needle. Compared to HCV, HIV, and other blood-borne infections, HBV infection can be effectively prevented by vaccines. 95% of vaccinated infants, 92% of <40-year-old HCWs, and 84% of >40-year-old HCWs develop antibodies to HBV and it has a half-life of 15-30 years . A safe and effective vaccine that offers 95% protection against hepatitis B is available. The HBV vaccine has been on the vaccination schedule since 1991, and the WHO has recommended that the HBV vaccine be made mandatory in all countries .
We explored that most or 77.8% of the HCWs are vaccinated for HBV while 17.5% of the participants reported that they’re not vaccinated. We could not compare this rate on HBV vaccination coverage within the results of the studies in Mongolia due to the unavailability of similar studies conducted after the Ministry of Health decision of vaccinating HCWs in 2012. This result is slightly lower than the vaccine coverage percentage in similar studies conducted in other countries. The vaccination coverage rate was 79% (2020) in Ethiopia  86,4% (2019) in China, 82.4% (2016) in Japan, 83.7% (2009) in Brazil, 85.3% (2006) in Italy and 84.9% (2004) in Belgium [19, 20].
However, the total rate of the HBV vaccine coverage is a bit more than 3/4 of the HCWs, only half (49.8%) of the HCWs born before 1992 had completed three doses of the vaccine, while 19.8% had not been vaccinated at all. Moreover, only 47.4% (538) of the total participants were vaccinated by three full doses, more than half 538 (60.9%) of the vaccinated ones. Only 1/3 of the HCWs born after 1992 were fully vaccinated.
Regarding vaccination coverage, physicians (81.0%) and nurses (80.8%) were vaccinated more than other occupations, which could be related to their knowledge level .
In terms of occupational risk, Q. Yaun et al.  found out that the rate in high-risk departments was lower than in low-risk departments, indicating the need to strengthen education targeted to HCWs with a high occupational exposure risk. However, the statistically significant difference was not observed among the groups; this study’s high, medium, and low risk.
The most common factors to get vaccinated are at the workplace and voluntary service. Therefore, the vaccination programs on HBV for healthcare workers should continue to focus on the provision of the service at the workplaces.
A study by S. Nagashima et al. found a gradual increase in anti-HBs titers after 1 and 5 months before the third dose of the HBV vaccine. A follow-up of 4 months showed a decrease in the titer of anti-HBs, indicating the need for post-vaccination testing at specific intervals. Two-dose re-vaccination prevents occupational infections, and 75% develop protective antibody titers . Therefore, the full dose vaccination is essential for HCWs.
We found out that the most common reason for not getting vaccinated or completing three doses of HBV vaccine was that they were busy, forgotten, did not know they needed 3 doses, and no one warned them. a similar study reported in Ethiopia that “Having obtained immunity from work”, “hospitals not providing hepatitis B vaccination activities” and “too busy to be vaccinated” were the main reasons mentioned by 40% (177/438), 40% (173/438) and 32% (140/438) of those respondents, respectively . Another study revealed that unavailability and high cost of the HBV vaccine were frequently mentioned reasons among medical students for not being vaccinated against HBV . Maybe the advocacy and education programs should be followed by promotional initiatives for getting full dose extensively and repeatedly.
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