Primer on Varicella (Chickenpox) Infection

November 07, 2017
Maria Nenita L. Salcedo, MD, FPPS

Recently we have encountered cases of students with Varicella or chickenpox infection. We have been following routine procedures in handling these cases. It is our concern that the number of cases may increase, thus we are issuing this primer to increase awareness and prevent an outbreak of chickenpox disease in our community.

What is varicella (chickenpox)?

Chickenpox is an infectious disease caused by the varicella-zoster virus, which results in a blister-like rash, itching, tiredness, and fever. The rash appears first on the trunk and face, but can spread over the entire body and may produce around 250 to 500 itchy blisters in unvaccinated persons.

How do you get chickenpox?

Chickenpox is highly infectious and spreads from person to person by direct contact or through the air from an infected person’s coughing or sneezing or from aerosolization of the virus from skin lesions. A person with chickenpox is contagious from 1-2 days before the rash appears and until all blisters have formed scabs. It takes from 10-21 days after exposure for someone to develop chickenpox. As such, all students with symptoms of fever should refrain from attending school as this may actually be an early sign for chickenpox. All students with chickenpox should self-quarantine at home until all blister-like rashes have dried up and the formed scabs have fallen off.

Can you get chickenpox even if you've been vaccinated?

Yes. About 15%–20% of people who have received one dose of chickenpox vaccine do still get chickenpox if they are exposed, but their disease is usually mild. Vaccinated persons who get chickenpox generally have fewer than 50 spots or bumps, which may resemble like bug bites more than the usual, fluid-filled blisters.
In 2006, it has been recommended that a routine two-dose varicella vaccination be given. In one study, children who received two doses of the chickenpox vaccine were three times less likely to get chickenpox than individuals who have had only one dose.

What is the chickenpox illness like?

In unvaccinated children, chickenpox most commonly causes an illness that lasts about 5-10 days. Children usually miss 5 or 6 days of school or childcare due to their chickenpox and have symptoms such as high fever, severe itching, an uncomfortable rash, and dehydration or headache. In addition, about 1 out of 10 unvaccinated children who get the disease will have a complication from chickenpox serious enough to visit a health-care provider. These complications may include infected skin lesions, dehydration from vomiting or diarrhea, or severe type of illnesses such as pneumonia and encephalitis.
In vaccinated children, chickenpox may still be present however with mild symptoms. About 25% to 30% of vaccinated children who get the disease will develop illness as serious as unvaccinated children.

Certain groups of people are more likely to have more severe illness with serious complications such as those who are immnocompromised or whose immune systems have been weakened because of illness or medications on long-term use of steroids.

Can chickenpox be prevented?

Yes, vaccination with the recommended two-doses of varicella vaccine prevents chickenpox in most people.

Can you get chickenpox more than once?

Yes, but such occurrences are uncommon. For most people, one infection appears to confer lifelong immunity.

Chickenpox in children is usually not serious. Why not let children get the disease?

It is not possible to predict who will have a mild case of chickenpox and who will have a serious or even deadly case of disease. Serious complications from chickenpox arise mostly from immunocompromised or pregnant patients (Fatality rate from chickenpox is 6.7 per 100,000 and are mostly adult cases). Anyone suspected of having chickenpox should also avoid close proximity with immunocompromised persons (i.e. the elderly, leukemia patients, cancer patients undergoing chemotherapy) and pregnant mothers.  Now that there is a safe and effective vaccine, it is not worth taking this chance.
Thank you very much for your attention and cooperation.
Prepared by:                    
Maria Nenita L. Salcedo, MD, FPPS
Head Physician
Junior High School Health Services