Research shows that vaccination of food handlers can control spread of hepatitis A

A new study shows that vaccination of food handlers is an effective way to reduce the spread of hepatitis A.

The study, published in the journal Frontiers, says hepatitis A remains a significant foodborne pathogen. Researchers analyzed 32 studies reporting HAV (hepatitis A virus) outbreaks linked to food handlers to assess whether vaccination could be an effective preventive strategy. 

Most of the outbreaks occurred in North America and Europe, with index cases almost exclusively identified among food workers. Outbreak sizes varied, though the majority involved fewer than 50 confirmed patients. The number of patients in the outbreaks was likely higher because some people do not seek medical treatment and others are not specifically tested for hepatitis A infection. Hepatitis A symptoms may not appear until 50 days after infection and can last up to six weeks.

“Considering HAV’s high transmissibility and the difficulty of timely outbreak detection, targeted vaccination of food handlers — especially those in high-risk settings or seasonal employment — emerges as a promising method of biological risk management in food industries. These considerations could support food industries in considering vaccination as a tool to prevent foodborne HAV transmission,” according to the research report.

In developed countries, most adults are susceptible to HAV infection because of limited vaccination rates. A number of outbreaks have been associated with contaminated food. This is likely influenced in part by increasing global food imports. 

The hepatitis A virus is primarily transmitted through the ingestion of food or water contaminated with microscopic amounts of feces from an infected individual, or via direct contact with an infected person. Even minimal quantities are sufficient to cause infection. This high transmission potential is partly due to the virus’s environmental stability. The virus can remain infectious in water, soil, on contaminated surfaces, in food and on food handlers hands.

“Its persistence is further enhanced at low temperatures, which allows it to survive for extended periods in various food matrices, including leafy greens, carrots, fennel, green onions, spinach, berries, aromatic herbs, ,and shellfish. For instance, HAV has been found to survive for months on frozen berries and remain infectious on surfaces depending on temperature and humidity conditions. Furthermore, under low humidity, it can persist on foods like lettuce, bell peppers, melon, and dried tomatoes,” according to the researchers.

Food handlers play a crucial role in preventing HAV transmission. If infected, they can transmit the virus through the food they prepare and have been identified as a major source of foodborne hepatitis A outbreaks. A single infected food handler can transmit the virus to hundreds of individuals during food harvesting, handling, preparation or distribution. This has been shown to significantly impact public health and healthcare costs.

Transmission by food handlers is not just a problem in restaurants. Throughout the food production chain, agricultural products undergo multiple stages of handling, increasing the risk of cross-contamination by infected workers or contaminated surfaces. 

Washing hands with water may reduce the viral load, but is insufficient for complete removal of the virus, according to the research report. Vaccination of food workers is the only method to ensure they do not infect others with the virus. 

Nevertheless, food safety strategies have generally prioritized environmental hygiene and sanitation over direct preventive measures such as vaccination. As of now, mandatory HAV vaccination for food handlers is enforced only in a few countries, such as Germany, while in most others it remains voluntary or merely recommended.

“It should be emphasized that the current social climate leads many people to find temporary or even seasonal jobs in food service, thereby exponentially expanding the pool of individuals who should undergo HAV vaccination and making monitoring virtually impossible. It is therefore crucial to implement the education about food safety among both permanent and temporary food handlers,” the researchers wrote.

“From the perspective of individual food business owners, the direct economic benefits of vaccinating their employees, although not immediately apparent — especially in regions with a low incidence of HAV — could be considered both to prevent business disruptions resulting from infectious episodes and to comply with major food safety regulations.”

According to the researchers, HAV vaccination can be an effective tool for preventing outbreaks. Therefore, they say, employer and employee participation in vaccination within the food industry should be encouraged through public incentives or subsidies.

(To sign up for a free subscription to Food Safety News, click here)

Source: https://www.foodsafetynews.com/2025/07/research-shows-that-vaccination-of-food-handlers-can-control-spread-of-hepatitis-a/