How Long Does Hep A Vaccine Last

Thanks to vaccines, many serious infections and diseases that took countless lives are now almost a thing of the past. In fact, hepatitis A incidence rate has dwindled by an amazing 95% since the vaccine was first introduced in the US in 1995.

But in 2016, there has been an increase in hep A cases as a result of food imports. And this makes it all the more important to get a shot of hep A vaccine. But you may still wonder how long does hep A vaccine last?

How Long Are You Protected?

Unfortunately, it is still hard to pinpoint the precise duration of the hep A vaccine. On the bright side, children who received a three-dose vaccine and adults who received a two-dose vaccine should be safe for 20 years.

In addition, some studies suggest that the vaccine antibodies may be present for forty or more years. This is particularly true for vaccinated children.

So, it is obvious that the vaccine may last for quite a while. However, you should still get a better understanding of the infection itself and the revaccination requirements.

What Is Hepatitis A?

In a nutshell, hep A is a liver infection caused by the hepatitis A virus. Since the liver is a major organ, this can be quite serious and some reports suggest that about 42% of the afflicted had to be hospitalized.

Hep A patients often feel very sick. Nevertheless, some people might not exhibit any symptoms at all. But when the symptoms do occur, they appear all of a sudden and include fatigue, nausea and vomiting, abdominal pain, and fever. Of course, signs of a dysfunctional liver will be on display.

Patients often have dark urine and clay-colored diarrhea. This is usually accompanied by loss of appetite, joint pain, and jaundice. It’s worth noting that jaundice does not usually appear in young children (under the age of 6).

Hepatitis A infection has quite a long incubation period of about 28 days on average. But, depending on some specific conditions, it may go up to 50 days. In addition, this liver infection is not easy to shake off. The symptoms usually persist for about two months. In 10 to 15% of the cases, the infection may last up to half a year.

This might sound alarming, but you may rest easier to know that hepatitis A is not a chronic condition. In fact, the IG antibodies developed during the infection would prevent it from ever occurring again.

Who Should Get Vaccinated?

The common practice in most of the developed world is to vaccinate all children at the age of one. And it is highly recommended to get vaccinated or revaccinated if you are at a greater risk of contracting the infection. This goes double for people who might be prone to hep A complications.

Those who are at greater risks can be divided into several categories. Frequent travelers to counties with high incidences of hepatitis A. It may not be enough to just maintain good hygiene, mind your food, and stay in high-end hotels.

People who work with primates might also be at greater risks of contracting hep A infection. The same goes for liver disease patients, those with clotting disorders, and homosexual/bisexual men.

The Hep A Vaccine and How It’s Administered

The hep A vaccine is an inactivated vaccine shot which contains dead hepatitis A virus. And in light of the recent anti-vaccination lobby, it should be stated that this vaccine is perfectly safe. Since its first introduction in 1995, millions of people have been inoculated without any serious complications.

Some minor side effects may appear, including soreness in the injection site, mild fever, and fatigue. These symptoms disappear on their own after a few days and allergic reactions to the vaccine are very rare. What’s more, this vaccine doesn’t pose any threat to pregnant women or the fetus.

As for the type of hep A vaccine in the US, there are two licensed single-antigen vaccines (VAQTA and HAVRIX) and a combination vaccine called TWINRIX. For the shots, you can get any combination of the above.

It doesn’t interfere with other vaccines so it can be administered at the same time as other vaccines like the ones for diphtheria, polio, cholera, yellow fever, etc. The injection area is, of course, different.

As mentioned, two doses of the vaccine are required for 20-plus-years of protection. In general, at least 6 months should go by between the shots. Adults receive the vaccine in the upper arm muscle and children in the thigh muscle.

Other Important Hepatitis A Vaccine Facts

People who are on hemodialysis and those with AIDS shouldn’t worry – it’s safe for them to get vaccinated since it’s an inactivated vaccine. What’s more, there is no harm in receiving additional shots if a person lost his medical history.

In some cases, prevaccination testing may apply. This is usually done to keep the vaccination cost down and may include people of certain ethnic groups and those who live in areas with high hep A incidence rate. The same rule applies to intravenous drug users.

The protection usually begins two to four weeks after the first shot. In light of the long incubation period of the hepatitis A virus, the protection may start right away.

Hep A isn’t treated with any antivirals and the liver has a remarkable ability to self-regenerate. Doctors usually prescribe sufficient hydration, plenty of rest, and proper nutrition, though some people might need to be hospitalized for additional medical care.

The Final Shot

How long does hep A vaccine last? If properly administered, it can last well into your adulthood. Nevertheless, it wouldn’t hurt (at least not too much) to get revaccinated if you are traveling to areas known for hep A infections.

 

References:

https://www.fda.gov/downloads/BiologicsBloodVaccines/Vaccines/ApprovedProducts/UCM224555.pdf
https://www.fda.gov/downloads/BiologicsBloodVaccines/Vaccines/ApprovedProducts/UCM110049.pdf
https://www.fda.gov/downloads/BiologicsBloodVaccines/Vaccines/ApprovedProducts/UCM110079.pdf
https://wwwnc.cdc.gov/travel/yellowbook/2018/infectious-diseases-related-to-travel/hepatitis-a
https://www.ncbi.nlm.nih.gov/pubmed/1335649
https://www.ncbi.nlm.nih.gov/pubmed/1475999
http://www.immunize.org/catg.d/p4204.pdf
https://www.ncbi.nlm.nih.gov/pubmed/26190091
https://www.ncbi.nlm.nih.gov/pubmed/28092416
https://www.cdc.gov/hepatitis/hav/havfaq.htm

Comments

comments