[Hepatitis A outbreak in a day care center and household transmission]

Hepatitis A occurrence and outbreaks in Europe over the past two decades: A systematic review

Hepatitis A (HA) is a vaccine-preventable liver disease with >170 million new cases occurring yearly. In recent outbreaks in the USA, hospitalization and case-fatality ratios were >60% and ~1%, respectively. In Europe, endemicity persists and outbreaks continue to occur. We performed a systematic literature review to understand the changes in HA occurrence in Europe over the past two decades. PubMed and Embase were systematically searched for peer-reviewed articles published between 1 January 2001 and 14 April 2021 using terms covering HA, 11 selected European countries, outbreaks, outcomes and HA virus circulation. Here, we focus on HA occurrence and outbreaks in the five countries with the largest population and the most comprehensive vaccination recommendations: France, Germany, Italy, Spain and the UK; 118 reports included data for these five European countries. Notification rates (≤9.7/100,000 population) and percentages of men among cases (≤83.0%) peaked in 2017. The number of person-to-person-transmitted cases and outbreaks decreased in children but increased in other risk groups, such as men who have sex with men (MSM). Sexually transmitted outbreaks in MSM clustered around 2017. Travel-related outbreaks were few; the proportion of travel-related cases decreased during the past two decades, while the number of domestic cases increased. Despite the existing risk-based vaccination recommendations, HA transmission shifted in proportions from travelers and children to other risk groups, such as MSM and older age groups. Because a substantial proportion of the European population is susceptible to HA, adherence to existing recommendations should be monitored more closely, and enhanced vaccination strategies should be considered.

The effect of policy changes on hepatitis A vaccine uptake in Arizona children, 1995-2008

OBJECTIVE

In 1995, the first hepatitis A vaccines became available for use. At that time, Arizona had the highest hepatitis A incidence of all 50 states. During that same time period, the Arizona State Immunization Information System (ASIIS) was created to collect information on all immunizations given in the state. Four state-level hepatitis A vaccination policies were enacted according to Centers for Disease Control and Prevention recommendations and local initiatives from 1996 to 2005. Our primary objective was to assess the impact of these policies on vaccine uptake in children.

METHODS

Immunization records from ASIIS were used to calculate yearly coverage of children with at least one reported hepatitis A vaccination between 1995 and 2008. Proportions vaccinated were calculated by age group (12-23 months, 24-59 months, 5-9 years, 10-14 years, and 15-19 years) for three regions: Maricopa County; Apache and Navajo counties; and the remaining 12 Arizona counties, which were grouped as one to reflect different target groups for the four policies examined. We calculated percent changes from before and after each policy implementation.

RESULTS

Significantly different percent changes were detected among the three regions that related to the four policies implemented. Percent change in uptake was consistently higher in the regions that were targeted for that specific policy.

CONCLUSIONS

Analysis of ASIIS data revealed a major effect of hepatitis A policy recommendations on vaccine uptake in Arizona. Targeting high-risk populations through vaccine recommendations and child care entry requirements was highly successful in achieving higher vaccination coverage.

[Study of a population outbreak of hepatitis A. Effectiveness of vaccination as a control measure]

OBJECTIVE

To describe an outbreak of hepatitis A in the city of Albacete (Spain) and to assess the effectiveness of the control measures implemented.

METHODS

When the outbreak was noted, definitions of a case were established. Clinical and epidemiological data were collected through a survey. The temporal-spatial distribution was identified through mapping and the epidemic curve. Health education and immunoglobulin (IG) administration were conducted as immediate prevention and control measures in the population at risk.

RESULTS

From January 2005 to January 2006, 62 cases were reported. The most affected age groups were school children and young adults. Transmission was person to person. The epidemic curve was divided into two periods. Initial control measures consisted of hygiene measures and IG administration to contacts. In the second period, these measures were complemented with vaccination against hepatitis A in students of the school centers of the two neighborhoods initially involved. Due to public alarm and spread of the outbreak to adjacent neighborhoods, vaccination was extended to schools close to those where cases had been detected. No cases were notified after the last vaccination in January 2006.

CONCLUSIONS

The use of vaccination after exposure to the hepatitis A virus in young adults and the school population seems to be an effective outbreak control measure.

[Community outbreak of hepatitis A in a marginal population. Vaccination for its control and acceptance of the measure]

OBJECTIVE

To study a community outbreak of hepatitis A in a marginal population and the public health response in order to bring it under control.

DESIGN

Descriptive study of the outbreak that occurred in February-June, 2004. An epidemiological survey was conducted to detect prior cases and active vigilance was set up. Case and susceptibility definitions were established.

SETTING

A gypsy population in Madrid, Spain. They had basic provision of sewerage, water supply and waste disposal.

PARTICIPANTS

A population of 550 in census; estimated population, 800. 70% were under 40 and 55% were illiterate.

INTERVENTIONS

Control measures were: a) health education activities to strengthen habits of hygiene, and b) immunisation of susceptible individuals. A total of 646 people were vaccinated, with the active help of staff from the Institute of Rehousing and Integration into Society.

RESULTS

The outbreak affected 26 people, with an average age of 8 (95% CI, 6.2-9.8), similar distribution by sex and 3.3% attack rate. Fourteen cases were students at state schools, not all in the same classes. There were 7 pairs of siblings among the cases. The diagnosis was conformed by serology in 17 cases. Five needed hospital admission.

CONCLUSIONS

The epidemic curve suggested person-person transmission. All those affected were under 20 years old. Vaccination was seen to be effective in controlling the outbreak. Interventions were assisted by intermediaries in order to respect the gypsies' cultural context and were well accepted.