Varicella (Chicken Pox) Prevention

Dr. Parang Mehta, MD.

Though chicken pox is considered a benign disease, it is not always so.  In the days before universal vaccination with the varicella vaccine, the USA recorded a hundred deaths a year attributable to chicken pox.

Chicken pox is mild in childhood, but can be a serious disease in teenagers and adults.  It is also dangerous in pregnancy, newborn babies, children with disorders of the immune system, and in those taking treatment with steroids or anti-cancer drugs.  Because of the potential for serious and even life threatening disease, chicken pox prevention is essential.

Isolation of Persons with Chicken Pox

Chicken pox is highly infectious, and people with chicken pox must be kept away from places where they can infect others.  Children in schools and daycare, and staff at these places, must stay away when they have chicken pox.  They should return only after all the skin rash has crusted, after which chicken pox is not infective.

Isolation should be done, but people with chicken pox are infectious for a day or two before the skin eruption appears

Isolation is only partially successful, though.  Chicken pox is infectious 24-48 hours before the rash appears.  During this day or two, when chicken pox cannot be diagnosed, a child with the illness can infect several of his classfellows and friends.  For this reason, vaccination is necessary for individual protection.

Met Someone With Chicken Pox?

If you or your child have spent some time with a person with chicken pox, or who developed chicken pox in the next 2 days, there is a risk of infection.

Chicken pox can occur in people who have had the disease or the vaccine earlier, but it is then relatively mild

People who have had chicken pox in the past are usually not susceptible.  It is very rare for anyone to get a second attack of chicken pox.  People who have received the chicken pox vaccine are also unlikely to get the disease.  If they do develop chicken pox (breakthrough varicella), they are likely to get a mild form of the disease.

For those people who have not had chicken pox before, nor received the vaccine, the options for protection are:

The varicella vaccine sounds like the best option, becauses it provides long term protection.  However, the vaccine cannot be given in pregnancy, and to babies less than a year old.  Certain other contra indications also exist for the vaccine.  The VZIG and acyclovir provide useful alternatives in these situations.

How Does Chicken Pox Spread?

It spreads very efficiently indeed.

Chicken pox is one of the most infectious disease in human beings.  Close contact, as occurs when one person in the household has the disease, puts all others at 80-100% risk of developing chicken pox.  Lesser contact, as in school or daycare, also carries a 60-80% risk of disease.

Chicken pox spreads through the air, and through direct contact.  The chicken pox virus is in nasal secretions, coughed droplets, and in the fluid in the skin rash lesions.  Children who have shared a classroom, daycare room, or any other common space breathe the virus in and get infected.  Children also get infected by direct contact with persons who have active skin lesions.

People with chicken pox become infectious before the rash appears.  The virus is being spread for 24-48 hours before the rash.  This allows one infected child to infect several of his classmates before he is diagnosed and isolated.

Herpes zoster is a disease caused by the varicella zoster virus -- the same disease that causes chicken pox.  Children can sometimes get chicken pox by close contact with a person who has herpes zoster.

 

The Chicken Pox Vaccine
Chicken Pox in Children

 

Last Revision: May 22, 2020