The Chickenpox-Shingles connection
When someone I knew got shingles recently, I found that lots of people were uncertain about various aspects of the disease and its relationship to chickenpox. And I’m not surprised as it’s quite confusing! I hope that this makes it clearer.
One virus – two diseases
(See the accompanying flow charts)
A virus called VZV (varicella zoster virus) causes both chickenpox and shingles.
You have to catch chickenpox from someone else.
But you can’t catch shingles from anyone else. It comes entirely from you.
Shingles arises from VZV that never left your body after you got chickenpox. It can appear at anytime after chickenpox, whether it be one year or seventy years later.
If you have had chickenpox before, you can’t catch chickenpox from someone with chickenpox.
If you have had chickenpox before, you can’t catch chickenpox from someone with shingles.
If you have had chickenpox before, you can’t catch shingles from someone with shingles. If you have had chickenpox before, you can’t catch shingles from someone with chickenpox.
If you have never had chickenpox before, you can catch chickenpox from someone with chickenpox. It is easy to get infected by someone with chickenpox because the virus is breathed out everywhere.
If you have never had chickenpox before, you can catch chickenpox from someone with shingles. But it is much harder to catch chickenpox from someone with shingles because you have to touch the shingles rash or things that have been in contact with the shingles rash e.g. clothing, bedding.
Does having shingles mean that I have an underlying problem with my immune system?
Usually no. Most people with shingles develop it later in life as our immune systems dwindle as a normal part of the aging process. But it can occur at any time in healthy people, even in children.
However, shingles can occasionally unmask an underlying problem with the immune system like cancer or AIDS.
Can
shingles recur?
Although the risk is low, shingles can happen again. That is why the new shingles vaccine is recommended for people aged 60 or over, even if they have had shingles before.
Is there a vaccine
for shingles?
Yes, there is. In the US, it is recommended for people aged 60 or over, even if they have had shingles before. While shingles can still occur in vaccinated people, the risk of developing shingles and chronic pain from shingles (the dreaded postherpetic neuralgia) is much less. PHN is postherpetic neuralgia. It is severe long-term pain following an attack of shingles. The best way to prevent PHN is by taking antiviral tablets (acyclovir, famciclovir or valaciclovir) within three days of developing the shingles rash. So if you suspect shingles, see your doctor as soon as possible.
Is there a vaccine for
chickenpox?
Yes, there is. It is essentially the same as the shingles vaccine except that it has a lower dose of virus in it. It is part of the childhood immunisation schedule in many countries. The US used to recommend one dose in childhood but recently changed that to two. This change was implemented to reduce breakthrough cases of chickenpox in children who’d only been vaccinated once.
Is there anyone who should avoid the shingles and chickenpox vaccines?
The vaccine contains live virus so it should be avoided in those who with low immune systems and pregnancy. Similarly, those with allergies to any of the vaccine constituents should not be vaccinated.
The writer is an Associate Professor of Medicine at the Australian National University and a Senior Specialist in Infectious Diseases)