A primer on hepatitis A: Outbreaks, foodservice, and vaccination – NoroCORE Food Virology

A primer on hepatitis A: Outbreaks, foodservice, and vaccination

Over the past year and a half, and particularly over these past few months, you probably have seen news articles about a multistate outbreak of hepatitis A virus (HAV), primarily among homeless persons and/or drug users. (Of the more than 2,500 case reports the CDC has received from January 2017 through April 2018, 68% have been in these two categories.)

The first cases were identified in California back November 2016 and that outbreak has wound down after 700 cases and rigorous vaccination and sanitation efforts. There are similar outbreaks occurring in Arkansas, Indiana, Kentucky, Michigan, Missouri, Ohio, Tennessee, Utah, and West Virginia.

 

Hepatitis A and foodservice settings:

photo of a food handler assembling a sandwich wearing a black apron holding a submarine bun with lettuce on itAlong the way, we started seeing cases where people working at restaurants were also contracting HAV. (However to our knowledge, information on whether these are from the same strains of HAV has not been provided, so it is hard to say if the cases are linked aside from geographic overlaps.)

Just in the past few days, restaurants in Ohio, West Virginia, Tennessee, and now North Carolina have been reported as sites of potential HAV exposure. While we don’t have hard numbers on the usual incidence of HAV in restaurants, foodservice-related outbreaks of HAV are usually not so common.

Hepatitis A is spread in a number of ways, including direct contact, touching contaminated surfaces, consuming contaminated food or water (hence why places where food is served are sometimes involved), sexual activities, and rarely though blood contact. It can last on surfaces for months, which is why good sanitation and disinfection are needed whenever it comes around.

The good news is that HAV is preventable by a vaccine (which is not the case for other foodborne pathogens), even if you have already been exposed to the virus.

 

The virus and the vaccine:

Image of a hepatitis virus from the CDC

A hepatitis virus (type unknown). Image courtesy of the CDC. Public Health Image Library

After someone is exposed to the hepatitis A virus, it takes about a month (2-7 weeks) for them to show symptoms. HAV actually affects children and adults differently. Around 70% of children under six who contract the virus show no symptoms at all, whereas adults tend to experience outward symptoms and are more likely to require hospitalization for supportive care. The normal symptoms include fever, loss of appetite, nausea, abdominal pain, and jaundice (yellowing of the skin and eyes). In rare cases, liver failure can occur, more often to those who are over 50 or have an underlying liver disease.

The vaccine is very effective at preventing HAV when given as a 2-dose series (or a 3-dose series that also has hepatitis B). The HAV vaccine is usually offered at no cost by insurance plans due to the Affordable Care Act.

It is a common core vaccine for children in about half of US states, and completing the vaccine series grants lifetime immunity to the virus. In fact, since the vaccine began being recommended in 1996, the number of cases each year in the US has dropped from 31,000 to 1,500!

In the case of a restaurant realizing one of their employees has HAV, their usual course of action is to vaccinate their staff and those who ate at the establishment in the last two weeks (or in some cases, give immune globulin). Sometimes special vaccination clinics are set up with the help of public health departments to make it more convenient for patrons to receive the vaccine. The two-week window is because the virus is slow and needs time to incubate in the body. If you receive the vaccine early enough, your body can generate immunity in time to keep you from getting sick, even if you were already infected.

Food safety and public health groups over the years have recommended that foodservice employees receive the vaccine. The reason is that while foodservice employees are not more likely to be exposed to the virus because of their work, they have the chance to infect many others if they do get HAV. The CDC has not been recommending all foodservice workers be vaccinated in the current case because they have not been the main population involved in the outbreaks.

 

Why many Americans are susceptible to HAV:

Unfortunately, many US adults have not been vaccinated for HAV (though their children may have been), and are susceptible to the virus. Part of this is because HAV is not endemic to (normally found in) the United States. In places where the virus is endemic, people are normally exposed to it as children, experience a mild or silent illness, and then have natural immunity from then onward. But in the US, most of us were never exposed to the virus in this way, and so we are at risk of HAV infection should it come around. (On the flipside, since HAV is uncommon in the US, most people are never exposed to it.)

The current CDC guidelines do not suggest that everyone needs to be vaccinated for HAV, but it is something a person can request. The recommendations focus on those who are most at-risk of acquiring HAV, such as people who travel to or are adopting children from places where HAV is common, drug users, and those who work with nonhuman primates.

 

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