Why doesn’t the UK vaccinate against chickenpox?

The chickenpox vaccine, also known as the varicella vaccine, is a safe and effective way to prevent chickenpox. It has been adopted by many countries as part of their standard vaccination schedule. However, some countries, particularly the UK, do not vaccinate against chickenpox. In this post we’ll briefly explore why.

Image by Petras Gagilas via Flickr

The chickenpox vaccine is safe

As we’ve previously discussed on this blog, the chickenpox vaccine is safe. Even in countries where the chickenpox vaccine has not been widely adopted, the safety of the vaccine is not in question. Getting chickenpox can lead to complications, hospitalization, and even death. Chickenpox is particularly risky in newborns, adults, pregnant women, and individuals with weakened immune systems. Even in the best-case outcome, it places a financial burden on families with working parents who must stay home to care for their children.

By now, you’re probably asking yourself “if the chickenpox vaccine is safe, why isn’t it widely adopted?” To answer this question, it is necessary to understand the relationship between chickenpox and shingles.

What is shingles?

Shingles is a painful disease that affects nerves. According to the National Institute on Aging, it can “cause burning, shooting pain, tingling, and/or itching, as well as a rash and blisters”. It carries the risk of complications which include damage to nerves and vision, as well as infection from the blisters. The pain that accompanies shingles is quite debilitating and can last a long time.

The virus that causes shingles is the same one that causes chickenpox: the varicella zoster virus. After recovering from chickenpox, the virus lies dormant in some of our nerves. For one third of the population, the virus reappears later in life in the form of shingles. Although we do not know exactly why it reappears in some people and not in others, it is thought that aging and/or a weakened immune system play a role in the virus’ reappearance.

How can we prevent shingles?

The easiest way to prevent shingles is to get vaccinated against chickenpox: if you don’t get chickenpox, then you never get the varicella zoster virus.

Today, there are also vaccines against shingles. In the United States, there are two vaccines that are approved to prevent shingles and they have different recommendations. You can learn more about them from the CDC.

Additionally, frequent exposure to the varicella zoster virus prevents shingles from emerging. Basically, coming into contact with people who have chickenpox acts as a vaccine against shingles.

Why some nations have not adopted the chickenpox vaccine

There are two primary reasons why some nations have not adopted the chickenpox vaccine:

  1. It is riskier to get chickenpox as an adult than as a child. Consequently, there’s a concern that a childhood immunization program will “drive up the age at which those who are non-immune get the illness”.
  2. A childhood immunization program might increase the incidence of shingles since adults will no longer encounter the varicella zoster virus.

As a consequence of these concerns, some countries are waiting it out to see what happens in countries that have adopted the chickenpox vaccine. However:

  1. Although the chickenpox vaccine might hypothetically drive up the age at which those who are non-immune get the illness, we have not seen this happen since the chickenpox vaccine was implemented in the US in 1995.
  2. Using children who have chickenpox essentially as an adult vaccine against shingles has ethical challenges. As previously mentioned, chickenpox is not a risk-neutral disease. I’m flummoxed by the idea that it’s OK to let kids get sick with a potentially devastating disease to prevent adults from getting shingles. Thankfully, today there’s a effective vaccine against shingles, so this argument no longer holds water.
Each year, more than 3.5 million cases of chickenpox, 9,000 hospitalizations, and 100 deaths are prevented by the chickenpox vaccine in the United States.
SciMoms guide to the chickenpox vaccine. Data from the CDC.

The benefits of the chickenpox vaccine

The CDC has estimated the impact of the chickenpox vaccine and has stated:

“Each year, more than 3.5 million cases of varicella, 9,000 hospitalizations, and 100 deaths are prevented by varicella vaccination in the United States”.

Hopefully, as more data is gathered on the public health benefits of the chickenpox vaccine, more countries can adopt it as part of their national immunization programs.