Chickenpox and Travelling – Are You at Risk?
As a child born in the 1980’s chickenpox was a common childhood illness. Parents would often bring their children to “chickenpox parties” to deliberately expose them to the disease to build immunity at an early age. While most children infected with chickenpox experience mild illness serious complications can occur, most commonly in infants, adults, pregnant women, and immunocompromised people. Complications of chickenpox can result in death. If you are an adult who is susceptible to chickenpox, you may be at higher risk of severe illness and complications from chickenpox.
Before the introduction of a chickenpox vaccine there were about 350,000 cases each year in Canada, and 1,500 to 2,000 chickenpox related hospitalizations. Since the introduction of the chickenpox vaccine program in the 2000’s cases in Canada have decreased substantially and the risk of getting infected in Canada is low. But what about when we travel? As of 2018, 18% of countries have implemented chickenpox vaccine programs. Depending on where you travel, there could be more chickenpox virus in circulation putting you at increased risk of being exposed to a highly contagious disease. Should you be concerned?
Chickenpox, also known as varicella, is a highly contagious disease caused by the varicella zoster virus (VZV). It spreads easily from person to person through the air from an infected person’s respiratory secretions, or by direct contact with skin lesions. Someone susceptible to chickenpox can also catch the disease through contact with the blisters of someone infected with shingles.
Chickenpox is generally a mild disease in children causing 250-500 red, itchy blisters. Complications of chickenpox can include bacterial infections of the skin, pneumonia, and encephalitis (swelling of the brain). Infants, adults, pregnant women, and people who are immunocompromised are at higher risk of complications from chickenpox. About 1 in 3,000 adults may die from the disease.
After infection as chickenpox the virus remains dormant and can reactivate later in life, causing shingles.
Where is the risk?
Chickenpox is a risk worldwide. The chickenpox vaccine is routinely given to children in Canada, the US, Australia, New Zealand, Japan, most countries in Europe, Central and South America, and some countries in the middle East. While the risk of chickenpox in these parts of the world may be lower than in countries where there are no vaccination programs for chickenpox, there is risk of the disease in all destinations worldwide. The risk becomes higher when visiting countries where the chickenpox vaccine is not routinely given.
Are you susceptible to chickenpox?
You are generally considered immune to chickenpox if you are:
- An adult ≥ 50 years of age even if you don’t remember having the disease as a child or
- Self-report a history or physician diagnosis of chickenpox prior to 2004, if you were older than 1 year of age or
- Have blood serology proving you are immune to varicella or
- Received 2 doses of the chickenpox vaccine after 1 year of age.
You may be susceptible to chickenpox if you:
- Had the chickenpox disease after 2004 because the number of infections decreased substantially after introduction of the vaccine. If you have a self-reported history or physician diagnosis of chickenpox after 2004, a blood test is required to prove immunity. Or
- Had the chickenpox before 1 year of age and have not received 2 doses of the vaccine or
- Are younger than 50 years of age and have not had the chickenpox disease or 2 doses of the vaccine or
- Only had one dose of the chickenpox vaccine.
The chickenpox vaccine is routinely given to children in BC as 2 doses at 1 year of age and again at 4-6 years of age. It is also provided free to susceptible adults as 2 doses separated by at least 6 weeks.
The chickenpox vaccine is safe and effective. The efficacy of the chickenpox vaccine in children is estimated to be 94.4% after a single dose, and 98.3% after a second dose. Side effects are generally mild and include pain, redness, and swelling at the injection site, fever, or a chickenpox-like rash.
Routine chickenpox vaccination began in BC in 2004. At this time the vaccine was given as a single dose to susceptible children at school entry and in grade 6 (birth cohorts 1993 and 1999). Routine vaccination at 1 year of age began in January 2005 (birth cohort January 1, 2004). A second dose of chickenpox vaccine was recommended beginning in 2012 (routinely at 4-6 years of age and catch-up program in grade 6 in 2012/13 – 2016/17). Individuals born 1993-2001 may be missing a second dose of varicella vaccine.
If you are travelling and think you may be susceptible to chickenpox, contact TravelSafe Clinic at 604-251-1975 to book a pre-travel consultation or vaccine appointment.