Impact of the national targeted Hepatitis A immunisation program in Australia: 2000-2014

Hepatitis A virus infection

Hepatitis A is a vaccine-preventable infection caused by the hepatitis A virus (HAV). Over 150 million new infections of hepatitis A occur annually. HAV causes an acute inflammatory reaction in the liver that usually resolves spontaneously without chronic sequelae. However, up to 20% of patients experience a prolonged or relapsed course and <1% experience acute liver failure. Host factors, such as immunological status, age, pregnancy and underlying hepatic diseases, can affect the severity of disease. Anti-HAV IgG antibodies produced in response to HAV infection persist for life and protect against re-infection; vaccine-induced antibodies against hepatitis A confer long-term protection. The WHO recommends vaccination for individuals at higher risk of infection and/or severe disease in countries with very low and low hepatitis A virus endemicity, and universal childhood vaccination in intermediate endemicity countries. To date, >25 countries worldwide have implemented such programmes, resulting in a reduction in the incidence of HAV infection. Improving hygiene and sanitation, rapid identification of outbreaks and fast and accurate intervention in outbreak control are essential to reducing HAV transmission.

[Epidemiological behavior of hepatitis A in Barranquilla, Colombia, in the period 2013-2017]

OBJECTIVE

To analyze the epidemiological behavior of hepatitis A in the district of Barranquilla (Colombia), in the period 2013-2017.

MATERIALS AND METHODS

Descriptive study, in which the database of all hepatitis A cases reported in the district of Barranquilla during the observation period were retrospectively reviewed.

RESULTS

There were 293 new cases of hepatitis A reported in the district of Barranquilla, of which 62.4% occurred in men and 37.6% in women. The age groups most affected by the disease were adults (39.6%), followed by young people and schoolchildren (15%, respectively). The incidence of hepatitis A in the district of Barranquilla decreased between 2013 and 2016 from 10.9 to 1.5 cases per 100 000 inhabitants; however, in 2017 there was a slight increase to 2.5 cases per 100 000 inhabitants.

CONCLUSIONS

Hepatitis A is an event of interest for public health in the district of Barranquilla, and the behavior of its incidence has had a downward trend in recent years.

Zero- or missed-dose children in Nigeria: Contributing factors and interventions to overcome immunization service delivery challenges

'Zero-dose' refers to a person who does not receive a single dose of any vaccine in the routine national immunization schedule, while 'missed dose' refers to a person who does not complete the schedule. These peopleremain vulnerable to vaccine-preventable diseases, and are often already disadvantaged due to poverty, conflict, and lack of access to basic health services. Globally, more 22.7 million children are estimated to be zero- or missed-dose, of which an estimated 3.1 million (∼14 %) reside in Nigeria.We conducted a scoping review tosynthesize recent literature on risk factors and interventions for zero- and missed-dosechildren in Nigeria. Our search identified 127 papers, including research into risk factors only (n = 66); interventions only (n = 34); both risk factors and interventions (n = 18); and publications that made recommendations only (n = 9). The most frequently reported factors influencing childhood vaccine uptake were maternal factors (n = 77), particularly maternal education (n = 22) and access to ante- and perinatal care (n = 19); heterogeneity between different types of communities - including location, region, wealth, religion, population composition, and other challenges (n = 50); access to vaccination, i.e., proximity of facilities with vaccines and vaccinators (n = 37); and awareness about immunization - including safety, efficacy, importance, and schedules (n = 18).Literature assessing implementation of interventions was more scattered, and heavily skewed towards vaccination campaigns and polio eradication efforts. Major evidence gaps exist in how to deliver effective and sustainable routine childhood immunization. Overall, further work is needed to operationalise the learnings from these studies, e.g. through applying findings to Nigeria's next review of vaccination plans, and using this summary as a basis for further investigation and specific recommendations on effective interventions.

Monitoring the incidence and causes of disease potentially transmitted by food in Australia: Annual report of the OzFoodNet network, 2016

Abstract

In 2016, a total of 44,455 notifications of enteric diseases potentially related to food were received by state and territory health departments in Australia. Consistent with previous years, campylobacteriosis (n = 24,171) and salmonellosis (n = 18,060) were the most frequently-notified infections. Notable increases in incidence were observed for shiga toxin-producing Escherichia coli (n = 343; 166% increase), shigellosis (n = 1,408; 93% increase), campylobacteriosis (33% increase) and salmonellosis (30% increase) when compared with the historical five-year mean. The extent to which the introduction of culture-independent testing as a method of diagnosis has contributed to these increases remains unclear. In total, 188 gastrointestinal outbreaks, including 177 foodborne outbreaks, were reported in 2016. The 11 non-foodborne outbreaks were due to environmental or probable environmental transmission (nine outbreaks) and animal-to-person or probable animal-to-person transmission (two outbreaks). No outbreaks of waterborne or probable waterborne transmission were reported in 2016. Foodborne outbreaks affected 3,639 people, resulting in at least 348 hospital admissions and four deaths. Eggs continue to be a source of Salmonella Typhimurium infection across the country: 35 egg-related outbreaks, affecting approximately 510 people, were reported across six jurisdictions in 2016. Three large multi-jurisdictional Salmonella outbreaks associated with mung bean sprouts (n = 419 cases); bagged salad products (n = 311 cases); and rockmelons (n = 144 cases) were investigated in 2016. These outbreaks highlight the risks associated with fresh raw produce and the ongoing need for producers, retailers and consumers to implement strategies to reduce potential Salmonella contamination.

Hepatitis A vaccination and its immunological and epidemiological long-term effects - a review of the evidence

Hepatitis A virus (HAV) infections continue to represent a significant disease burden causing approximately 200 million infections, 30 million symptomatic illnesses and 30,000 deaths each year. Effective and safe hepatitis A vaccines have been available since the early 1990s. Initially developed for individual prophylaxis, HAV vaccines are now increasingly used to control hepatitis A in endemic areas. The human enteral HAV is eradicable in principle, however, HAV eradication is currently not being pursued. Inactivated HAV vaccines are safe and, after two doses, elicit seroprotection in healthy children, adolescents, and young adults for an estimated 30-40 years, if not lifelong, with no need for a later second booster. The long-term effects of the single-dose live-attenuated HAV vaccines are less well documented but available data suggest they are safe and provide long-lasting immunity and protection. A universal mass vaccination strategy (UMV) based on two doses of inactivated vaccine is commonly implemented in endemic countries and eliminates clinical hepatitis A disease in toddlers within a few years. Consequently, older age groups also benefit due to the herd protection effects. Single-dose UMV programs have shown promising outcomes but need to be monitored for many more years in order to document an effective immune memory persistence. In non-endemic countries, prevention efforts need to focus on 'new' risk groups, such as men having sex with men, prisoners, the homeless, and families visiting friends and relatives in endemic countries. This narrative review presents the current evidence regarding the immunological and epidemiological long-term effects of the hepatitis A vaccination and finally discusses emerging issues and areas for research.

Annual Immunisation Coverage Report 2017

This eleventh national annual immunisation coverage report focuses on data for the calendar year 2017 derived from the Australian Immunisation Register (AIR) and the National Human Papillomavirus (HPV) Vaccination Program Register. This is the first report to include data on HPV vaccine course completion in Aboriginal and Torres Strait Islander (Indigenous) adolescents. 'Fully immunised' vaccination coverage in 2017 increased at the 12-month assessment age reaching 93.8% in December 2017, and at the 60-month assessment age reaching 94.5%. 'Fully immunised' coverage at the 24-month assessment age decreased slightly to 89.8% in December 2017, following amendment in December 2016 to require the fourth DTPa vaccine dose at 18 months. 'Fully immunised' coverage at 12 and 60 months of age in Indigenous children reached the highest ever recorded levels of 93.2% and 96.9% in December 2017. Catch-up vaccination activity for the second dose of measles-mumps-rubella-containing vaccine was considerably higher in 2017 for Indigenous compared to non-Indigenous adolescents aged 10-19 years (20.3% vs. 6.4%, respectively, of those who had not previously received that dose). In 2017, 80.2% of females and 75.9% of males aged 15 years had received a full course of three doses of human papillomavirus (HPV) vaccine. Of those who received dose one, 79% and 77% respectively of Indigenous girls and boys aged 15 years in 2017 completed three doses, compared to 91% and 90% of non-Indigenous girls and boys, respectively. A separate future report is planned to present adult AIR data and to assess completeness of reporting.

Annual Immunisation Coverage Report 2016

This tenth annual immunisation coverage report shows data for the calendar year 2016 derived from the Australian Immunisation Register (AIR) and the National Human Papillomavirus (HPV) Vaccination Program Register. After a decade of being largely stable at around 90%, 'fully immunised' coverage at the 12-month assessment age increased in 2016 to reach 93.7% for the age assessment quarterly data point in December 2016, similar to the 93.4% for the age assessment quarterly data point in December 2016 for 60 months of age. Implementation of the 'No Jab No Pay' policy may have contributed to these increases. While 'fully immunised' coverage at the 24-month age assessment milestone decreased marginally from 90.8%, in December 2015, to 89.6% for the age assessment quarterly data point in December 2016, this was likely due to the assessment algorithm being amended in December 2016 to include four doses of DTPa vaccine instead of three, following reintroduction of the 18-month booster dose. Among Indigenous children, the gap in coverage assessed at 12 months of age decreased fourfold, from 6.7 percentage points in March 2013 to only 1.7 percentage points lower than non-Indigenous children in December 2016. Since late 2012, 'fully immunised' coverage among Indigenous children at 60 months of age has been higher than for non-Indigenous children. Vaccine coverage for the nationally funded seasonal influenza vaccine program for Indigenous children aged 6 months to <5 years, which commenced in 2015, remained suboptimal nationally in 2016 at 11.6%. Changes in MMR coverage in adolescents were evaluated for the first time. Of the 411,157 ten- to nineteen-year-olds who were not recorded as receiving a second dose of MMR vaccine by 31 December 2015, 43,103 (10.5%) of them had received it by the end of 2016. Many of these catch-up doses are likely to have been administered as a result of the introduction on 1 January 2016 of the Australian Government's 'No Jab No Pay' policy. In 2016, 78.6% of girls aged 15 years had three documented doses of HPV vaccine (jurisdictional range 67.8-82.9%), whereas 72.9% of boys (up from 67.1 % in 2015) had received three doses.

Influenza vaccination in pregnancy among a group of remote dwelling Aboriginal and Torres Strait Islander mothers in the Northern Territory: The 1+1 Healthy Start to Life study

Remote-living Aboriginal and Torres Strait Islander women experience a higher burden of influenza infection during pregnancy than any other Australian women. Despite recommendations of inactivated influenza vaccination (IIV) in pregnancy, uptake and safety data are scarce for this population. We examined uptake of IIV in pregnancy and report adverse birth outcomes amongst a predominantly unvaccinated group of remote-living Aboriginal and Torres Strait Islander women from the Northern Territory (NT), using data from the 1+1 Healthy Start to Life study. Data were deterministically linked with the NT Immunisation Register to ascertain IIV exposure in pregnant women during 2003-2006 and 2009-2011 inclusive. Overall, IIV uptake in pregnancy was 3% (n=20/697 pregnancies); 0% (0/414) pre-influenza A(H1N1)pdm09 and 7% (20/293) post-influenza A(H1N1)pdm09 (2009-2011). Vaccine uptake was poor in this cohort and it is unclear at what stage this policy failure occurred. Women with known comorbidities and/or high risk factors were not targeted for vaccination. Much larger study participant numbers are required to validate between group comparisons but there was no clinically nor statistically significant difference in median gestational ages (38 weeks for both groups), mean infant birthweights (3,001 g unvaccinated vs 3,175 g IIV vaccinated), nor birth outcomes between the few women who received IIV in pregnancy and those who did not. There were no stillbirths in women who received an IIV in pregnancy.

Modelling the decline and future of hepatitis A transmission in Australia

Hepatitis A incidence has declined in most countries through a combination of prevention measures, augmented through the use of a highly effective vaccine. In Australia, the proportion of the population susceptible to hepatitis A infection has declined over time due to high rates of opportunistic vaccination as well as the sustained inflow of seropositive immigrants from high-endemicity countries. These factors have contributed to a rapid decline in incidence. An age-structured hepatitis A transmission model incorporating demographic changes was fitted to seroprevalence and disease notification data and used to project incidence trends and transmission potential for hepatitis A in the general population. Robustness of findings was assessed through worst-case scenarios regarding vaccine uptake, migration and the duration of immunity. The decline in age-specific seroprevalence until the introduction of hepatitis A vaccine in 1994 was well explained through a declining basic reproduction number (R₀ ) that remained >1. Accounting for existing immunity, we estimated that the effective reproduction number (R_eff ) <1 in the general population of Australia since the early 1990s, declining more rapidly after the introduction of the hepatitis A vaccine. Future projections under a variety of scenarios support R_eff remaining <1 with continued low incidence in the general population. In conclusion, our results suggest that sustained endemic transmission in the general Australian population is no longer possible although risks of sporadic outbreaks remain. This suggests potential for local elimination of hepatitis A infection in Australia, provided that elimination criteria can be defined and satisfied in risk groups. The methodology used here to investigate elimination potential can easily be replicated in settings such as in the USA where sequential seroprevalence studies are supported by routine notification data.

In pursuit of control and elimination: update on hepatitis A and B epidemiology and prevention strategies

PURPOSE OF REVIEW

This review describes the impact of recommendations for routine immunization of infants and children against hepatitis A and hepatitis B, the changing epidemiology of these infections, and the remaining challenges to controlling or eliminating these diseases in the United States.

RECENT FINDINGS

Rates of hepatitis A and B have significantly declined because of childhood vaccination programs and long-term protection provided by infant immunization. However, hepatitis A immunization rates remain lower than other vaccines, and outbreaks continue to occur in part due to a growing number of susceptible adults. The Advisory Committee on Immunization Practice has updated pre and postexposure prophylaxis and travel recommendations for hepatitis A prevention in young infants, as well as recommendations to reduce ongoing perinatal transmission of hepatitis B.

SUMMARY

Pediatric healthcare providers should continue to immunize all infants against hepatitis A and B and ensure that no child outgrows the pediatric practice without being vaccinated. To address hepatitis A, providers should be aware of new recommendations for unimmunized travelers, use vaccines to prevent and control outbreaks, and ensure postexposure prophylaxis. Universal vaccination of infants against hepatitis B should begin before hospital discharge. The prevention of perinatal transmission is critical for control and possible eradication of hepatitis B.

The effectiveness and limitation of the national childhood hepatitis A vaccination program in the Republic of Korea: Findings from the Korean National Health and Nutrition Examination Survey (KNHANES), 2015

Background

Vaccination for hepatitis A virus (HAV) has been implemented as one of the national vaccination programs despite the epidemiological transition of HAV in the Republic of Korea. While the national HAV vaccination program is largely associated with the shift of socioeconomic trend in the country, concerns have been raised on the effectiveness of the HAV immunization. The objective of this study was to examine the epidemiological trend of HAV and assess the effectiveness of the nationwide HAV vaccination policy based on a nationally representative sample of the Korean population collected in 2015.

Methods

We analyzed anti-HAV of 5,856 respondents aged ≥10 years collected from Korean National Health and Nutrition Examination Survey (KNHANES) data in 2015. We estimated age-adjusted anti-HAV prevalence by sociodemographic and other characteristics. We evaluated the factors associated with anti-HAV positivity among each age group (10–19, 20–29, 30–45 and over 45 years old).

Results

The prevalence of anti-HAV among adults aged ≥10 years was 72.5% (95% confidence interval, CI, 73.7–71.4) in 2015. The lowest age-specific prevalence was among adults aged 20–29 years with 11.9% (95% CI 9.3–15.1%). The prevalence of anti-HAV among those aged 10–14 and 15–19 years was 59.7% (95% CI 52.7–66.4) and 24.0% (95% CI 19.5–29.3), respectively. The prevalence of anti-HAV among adults aged between 30 and 44 years rapidly increased from below 20% to above 90%. The prevalence of anti-HAV among adults aged ≥45 years was 97.8% (95% CI 96.0–97.6). Factors significantly associated with anti-HAV positivity among those aged 10–19 years old were young age, higher house income and high influenza vaccination rate. Compared to the respondents aged 10–19 years (those who were subject to the national childhood vaccine recommendation), those aged 20–29 years (those who were not subject to the recommendation) had low adjusted odds ratio (OR, 0.52 95% CI 0.34–.81 P-value = 0.004) for anti-HAV positivity.

Conclusions

The age-adjusted anti-HAV prevalence showed a U-shaped association, implying the high dependence of anti-HAV prevalence on age and the epidemiological shift. The inclusion of the hepatitis A vaccine into the national immunization recommendation was effective shown by the increase of immunity in the general population. However, the vaccination rate was low in the low-income group. Young adults aged 20–39 years may benefit from inclusion in the HAV vaccination program due to the significantly low vaccination rate.

Quantifying the population effects of vaccination and migration on hepatitis A seroepidemiology in Australia

Since licensure of hepatitis A vaccine in Australia in 1994, infection rates have declined to record lows. Cross-sectional serosurveys conducted over this period meanwhile have shown rising population immunity, particularly in young to middle-aged Australians. In this study, we performed a retrospective birth cohort analysis to estimate the contributions of infection, migration and vaccination towards increased levels of age specific hepatitis A seroprevalence in Australia. When aggregated across age, we find that two-thirds of the increase in population seropositivity (67.04%) between 1994 and 2008 was due to vaccination, just under one-third due to migration, with a negligible contribution from infection (<1%). Comparisons with other data sources reflecting vaccine uptake suggest the magnitude of this effect is realistic. We suggest that these results primarily relate to opportunistic vaccination and indicate the level of population immunity achievable through opportunistic programs providing further evidence for policy considerations around universal hepatitis A vaccine recommendations.