Changing pattern of hepatitis a virus epidemiology in an area of high endemicity

Prevalence of hepatitis A and E viruses in wastewater in Asian countries

Hepatitis A and E viruses (HAV and HEV, respectively) remain a significant global health concern despite advancements in healthcare and vaccination programs. Regular monitoring and vaccine efficacy of HAV are still lacking in different countries. This study aimed to investigate HAV and HEV prevalence in developed, developing, and least-developed Asian countries using wastewater as a surveillance tool. A total of 232 untreated wastewater samples were collected from six wastewater treatment plants, a sewage treatment plant, or an open drainage in six countries [Nepal (n = 51), Indonesia (n = 37), Thailand (n = 30), Vietnam (n = 27), the Philippines (n = 17), and Japan (n = 70)] between April and October 2022. Viruses in wastewater were concentrated by simple centrifugation or polyethylene glycol precipitation method, followed by viral RNA extraction and reverse transcription-quantitative polymerase chain reaction. HAV and HEV RNA were detected in the samples from Nepal (51 % for HAV and 2 % for HEV), Thailand (3 % for both viruses), and Japan (1 % for HAV and 24 % for HEV). Only HAV RNA was found in 11 % of the samples in Indonesia, whereas only HEV RNA was detected in Vietnam and the Philippines, with a positive ratio of 15 % and 12 %, respectively. These results highlighted the geographic variability in HAV and HEV prevalence, underscoring the need for localized public health strategies to address specific viral hepatitis challenges in each country.

Seroprevalence and incidence of hepatitis A in Southeast Asia: A systematic review

BACKGROUND

A previous review on hepatitis A virus (HAV) seroprevalence in 2005 categorized Southeast Asia as a low HAV endemicity region. In 2010, the World Health Organization modified this from low to low/medium endemicity, pointing out that these estimates were based on limited evidence. Since then, there has been no attempt to review HAV epidemiology from this region. We conducted a systematic review of literature to collect information on HAV incidence and seroprevalence in select countries in the Southeast Asian region, specifically, The Association of Southeast Asian Nations over the last 20 years.

METHODOLOGY

This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. From the relevant articles, we extracted data and conducted a risk of bias assessment of individual studies.

RESULTS

The search yielded 22 and 13 publications on HAV seroprevalence and incidence, respectively. Overall, our findings point to a very low HAV endemicity profile in Thailand and Singapore and evidence of a shift towards low HAV endemicity in Indonesia, Lao People's Democratic Republic, Malaysia, the Philippines, and Vietnam. Only Singapore, Thailand, Malaysia, and the Philippines have existing HAV disease surveillance and reported incidence rates below 1 per 100,000. Several outbreaks with varying magnitude documented in the region provide insights into the evolving epidemiology of HAV in the region. Risk of bias assessment of studies revealed that the individual studies were of low to medium risk.

CONCLUSIONS/SIGNIFICANCE

The available HAV endemicity profiles in Southeast Asian countries, aside from Thailand, are limited and outdated, but suggest an endemicity shift in the region that is not fully documented yet. These findings highlight the need to update information on HAV epidemiology through strengthening of disease surveillance mechanisms to confirm the shift in HAV endemicity in the region.

A review of immunogenicity and tolerability of live attenuated Hepatitis A vaccine in children

Changing epidemiology of Hepatitis A virus (HAV) has led to an increased susceptibility of adolescents and adults to the infection. Vaccination can remarkably reduce the incidence and associated morbidity of HAV infection. This review is focused on the safety and efficacy of H2 strain derived live attenuated Hepatitis A vaccine. We found the vaccine to be highly immunogenic with minimal or negligible safety issues. Moreover, a single dose of live attenuated vaccine persists a long term immune response and can be a preferred option for developing countries. In 2014, Indian Academy of Paediatrics (IAP) also updated their recommendations for H2 vaccine as a single dose as against the previous 2 dose schedule. A focused approach to include the vaccine in national immunization program should be explored.

Seroprevalence and susceptibility to hepatitis A in the European Union and European Economic Area: a systematic review

Most of the European Union (EU) and European Economic Area (EEA) is considered a region of very low hepatitis A virus (HAV) endemicity; however, geographical differences exist. We did a systematic review with the aim of describing seroprevalence and susceptibility in the general population or special groups in the EU and EEA. We searched databases and public health national institutes websites for HAV seroprevalence records published between Jan 1, 1975, and June 30, 2014, with no language restrictions. An updated search was done on Aug 10, 2016. We defined seroprevalence profiles (very low, low, and intermediate) as the proportion of the population with age-specific anti-HAV antibodies at age 15 and 30 years, and susceptibility profiles (low, moderate, high, and very high) as the proportion of susceptible individuals at age 30 and 50 years. We included 228 studies from 28 of 31 EU and EEA countries. For the period 2000-14, 24 countries had a very low seroprevalence profile, compared with five in 1975-89. The susceptibility among adults ranged between low and very high and had a geographical gradient, with three countries in the low susceptibility category. Since 1975, EU and EEA countries have shown decreasing seropositivity; however, considerable regional variability exists. The main limitations of this study are that the studies retrieved for analysis might not be representative of all EU and EEA publications about HAV and might have poor national representativeness. A large proportion of EU and EEA residents are now susceptible to HAV infection. Our Review supports the need to reconsider specific prevention and control measures, to further decrease HAV circulation while providing protection against the infection in the EU and EEA, and could be used to inform susceptible travellers visiting EU and EEA countries with different HAV endemicity levels.

Pattern of Hepatitis A Virus Epidemiology in Nursing Students and Adherence to Preventive Measures at Two Training Wards of a University Hospital

BACKGROUND

Nursing students can be exposed to patients with hepatitis A virus (HAV) and can represent a vehicle of transmission both for health personnel, patients and relatives.

OBJECTIVES

The aim of this study was to assess the risk of HAV infection in nursing students during their internship.

PATIENTS AND METHODS

A seroprevalence survey on HAV infection was performed on nursing students at the Cagliari university-hospital, together with the assessment of the compliance to preventive measures to decrease the risk of infection during their internship. Blood specimens were obtained from 253 students. All serum samples were tested for anti-HAV antibodies (IgG) by the enzyme-linked immunosorbent assay (ELISA). Compliance to preventive measures was recorded by trained personnel.

RESULTS

Overall HAV seropositivity in nursing students (mean age 24, range 17 - 45 years) was 3%. Compliance to preventive measures was not uniform (6% - 76%) and extremely low in some specific measures targeted to decrease the oral-fecal transmission.

CONCLUSIONS

The high proportion of susceptible nursing students can contribute to an increase in the risk of nosocomial transmission, especially when specific preventive measures are not completely applied. Nursing education packages, before starting medical internship, should be implemented in order to increase their compliance to preventive measures, especially in wards at higher risk. Vaccination should be considered in wards at higher risk.

Role of non-hepatotropic viruses in acute sporadic viral hepatitis and acute-on-chronic liver failure in adults

BACKGROUND

Acute viral hepatitis (AVH) is mostly caused by hepatitis E (HEV) and hepatitis A (HAV) viruses in India. This study was undertaken to find out the incidence of various hepatotropic and non-hepatotropic viruses in AVH and acute-on-chronic liver failure (ACLF) patients.

METHODS

Six-hundred and seventy-three adult patients of AVH and ACLF were screened for acute serological markers of hepatotropic (A, B, C, D, and E) and the non-hepatotropic cytomegalovirus (CMV) and Epstein-Barr virus (EBV).

RESULTS

Viral etiology profile in 295 samples with confirmed etiology were HEV in 155 (52.5 %); HAV in 43 (14.5 %); HBV in 35 (11.8 %); HCV in 1 (0.3 %); mixed viral etiology in 30 (10.1 %); and non-hepatotropic viruses, cytomegalovirus, and Epstein-Barr virus in 31 (10.5 %). Two-hundred and six patients (69.8 %) were AVH and 89 (30.1 %) ACLF. HEV was the commonest cause of infection in both the groups AVH (n = 95, 46.1 %) and ACLF (n = 60, 67.4 %). Twenty-nine (9.8 %) patients died on follow up; mortality was higher in ACLF (25/89, 28 %) than AVH group (4/206, 1.94 %; p < 0.001). The mortality was higher when HEV was the cause of acute event (20/29, 68.9 %). In AVH, mixed infection was more common as compared to ACLF (27 vs. 3, p < 0.001). Non-hepatotropic viruses contributed significantly higher infections in AVH as compared to ACLF (29 vs. 2, p = 0.002) patients.

CONCLUSIONS

HEV was an important cause of symptomatic hepatitis in both AVH and ACLF patients. Non-hepatotropic viruses like CMV and EBV were identified in a significant number of patients with AVH and much less frequently in ACLF.

Impact of Hepatitis A vaccination with a two-dose schedule in Panama: Results of epidemiological surveillance and time trend analysis

PURPOSE

In April 2007, Panama introduced Hepatitis A universal vaccination using a two-dose schedule (Havrix(®)junior; GSK Vaccines, Belgium). We assessed the impact of this hepatitis A vaccine three years after it was recommended for universal mass vaccination in Panama.

MATERIALS AND METHODS

Hepatitis A vaccination impact was assessed using two different approaches. The first approach used retrospective data (incidence and number of cases for all age groups), collected from the passive surveillance of the Epidemiologic Surveillance System of the Ministry of Health of hepatitis A and unspecified hepatitis before (2000-2006) and after (2008-2010) introduction of hepatitis A vaccine. The second approach was a prospective hospital-based active surveillance for hepatitis cases conducted in subjects (0-14 years) during 2009-2011 at three sentinel hospitals in Panama.

RESULTS

Overall, the annual incidence of hepatitis A and unspecified hepatitis in 2008, 2009 and 2010 were 13.1, 7.9 and 3.7 per 100,000 subjects, lower than the baseline incidence of 51.1 per 100,000 subjects. In comparison to the mean baseline period (2000-2006), there was an 82% mean reduction in the overall hepatitis-related outcomes (hepatitis A and unspecified hepatitis) after vaccine introduction (2008-2010) in all age groups. In the hospital-based surveillance (2009-2011), of the 42 probable viral hepatitis A cases, nine cases were confirmed as acute hepatitis A (8 in 2009, 1 in 2010). Of these confirmed cases, two belonged to the targeted vaccine group (1-4 years) but were not vaccinated.

CONCLUSIONS

Our study suggests that the introduction of two-dose hepatitis A vaccines in Panama has contributed to the reduction in the incidence of overall hepatitis-related outcomes for all age groups, suggesting herd protection. Additional monitoring is required to document a sustained long-term effect.

The prevalence of neutralizing antibodies against adeno-associated virus capsids is reduced in young Japanese individuals

Pre-existing antibodies against adeno-associated virus (AAV), caused by natural AAV infections, interfere with recombinant AAV vector-mediated gene transfer. We studied the prevalence of neutralizing antibodies against AAV serotypes 1, 2, 5, 8, and 9 in healthy subjects (n = 85) and hemophilia patients (n = 59) in a Japanese population. For healthy subjects, the prevalence of neutralizing antibodies against AAV serotypes 1, 2, 5, 8, and 9 was 36.5%, 35.3%, 37.6%, 32.9%, and 36.5%, respectively, while that in hemophilia patients was 39.7%, 28.8%, 35.6%, 32.9%, and 27.4%, respectively. There was no difference in the prevalence of neutralizing antibody against each AAV serotype between the healthy subjects and the hemophilia patients. The prevalence of neutralizing antibodies against all AAV serotypes increased with age in both healthy subjects and hemophilia patients. High titers of neutralizing antibodies against AAV2 (≥1:224) and AAV8 (≥1:224) were more evident in older individuals (≥42 years old). Approximately 50% of all screened individuals were seronegative for neutralizing antibodies against each AAV tested, while approximately 25% of individuals were seropositive for each AAV serotype tested. The prevalence of seronegativity for all AAV serotypes was 67.0% (healthy subjects, 68.6%; hemophilia patients, 65.0%) and 18.6% (healthy subjects, 20.5%; hemophilia patients, 15.7%) in young (<42 years old) and older subjects (≥42 years old), respectively. The findings from this study suggested that young subjects are more likely to be eligible for gene therapy based on AAV vectors delivered via an intravascular route because of the low prevalence of antibodies to AAV capsids.