Chickenpox Vaccine Does Not Cause Shingles In Seniors
Question: My parents are in their sixties. They have recently moved in with us in the ‘granny suite.’ They are still fairly healthy and active. Our youngest son is turning one next month; he is due to have chickenpox and other vaccines. A friend recently warned me that chickenpox vaccine can cause shingles in seniors. When I checked on the Internet, there are websites citing this link. I am worried about my parents getting shingles from our son. What do you think?
Answer:
No, chickenpox vaccine does not cause shingles in seniors. These websites are trying to use circumstantial evidence to blame chickenpox vaccine as the reason for the increase in shingles in seniors.
Both chickenpox and shingles are caused by the varicella zoster virus (VZV). Before chickenpox vaccine was introduced in 1990s, most children contract the virus at a young age and have chickenpox. A small percentage only got infected as adults and developed more serious complications, including pneumonia and encephalitis (inflammation of the brain). Although childhood chickenpox is relatively benign, there were occasional serious complications and death, especially in those who have weakened immunity.
As a result, chickenpox vaccine was developed and tested for many years before it was approved in North America. Two doses of the vaccine several months apart is extremely effective in preventing severe chickenpox infection. A small percentage of children are not fully protected; they can still develop very mild chickenpox when exposed to the virus.
Once a child has chickenpox, the virus stays in the body, hiding inside nerve cells close to the spinal cord. The virus remains dormant until one day, when it reactivates and spreads along the nerve to the skin, and breaks out with a rash that is called shingles. This is a painful eruption of blisters that can last for days to weeks, sometimes leaving the person with pain for a very long time.
Most of the time, shingles happen in seniors, most likely because they lose their immunity against the virus. This can also occur when a person’s immune system is weakened by stress, illness (especially cancer), or medical treatment.
Anyone who has had chickenpox can develop shingles later on in life. Therefore, your parents can have shingles from the virus already inside their body, but not from the chickenpox vaccine that your son is getting in the near future.
When your son gets the chickenpox vaccine, the virus will grow and multiply in his body. It is because this is a live vaccine with a weakened chickenpox virus. He may develop a mild rash, but not the typical blisters of chickenpox. He will shed a little bit of virus in his secretions. Occasionally, the chickenpox vaccine virus can spread from one child to another who has not been vaccinated, but it doesn’t cause significant infection. The vaccine virus will stay dormant in his nerve cells also. So far, research has shown that those who received chickenpox vaccine have a lower chance of developing shingles years down the road.
If you worry about your parents developing shingles, there is a new vaccine called Zostavax which can boost their immunity against chickenpox virus. It can reduce their chance of developing shingles, although it is still unclear how long this protection may last.
To summarize, chickenpox vaccine cannot cause shingles in your parents. You should go ahead and have your son immunized.