Vaccination

Varicella (Chickenpox)

Varicella is an acute infectious disease caused by the varicella-zoster virus, is highly contagious and has a worldwide distribution. Transmission is via droplets, aerosol or direct contact. Usually is a mild disease in childhood, but adults may have a more severe disease with higher incidence of complications. In temperate regions, varicella has a seasonal pattern with highest incidence during winter and early spring; in tropical areas, seasonality is not evident.

Adult travellers without history of varicella who travel from tropical to temperate climate countries may be at increased risk. Most adult travellers from temperate climate countries are immune, due to previous vaccination or to natural infection. Non-immunized children are at increased risk when they travel to countries with high incidence of varicella.

Several industrializaed countries have included varicella vaccination in their childhood national immunization programs, either with monovalent or with combined quadrivalent live attenuated vaccines. The two types of vaccine should be administered deep subcutaneously, both to adults and children 12 months of age and over. The monovalent varicella vaccine can be administered at the same time as other childhood vaccines (DTP/Hib/VIP, Hepatitis B, Influenza, Menc7, and MMR), as well as the combined quadrivalent Measles-Mumps-Rubella-Varicella or MMRV (DTP/Hib/VIP, Hepatitis B, Influenza and Menc7).

The schedule for both types of vaccine is as follows: at least one dose for children from one year to under 14 years of age, and two doses for older children/adolescents and adults, given 4-8 weeks apart. Children vaccinated at 12-18 months of age should receive a booster dose at 4-6 years of age.

These live vaccines, either mono or quadrivalent, should not be given to women known to be pregnant or who might become pregnant within three months after vaccination. Other contraindications and precautions include: anaphylactic reaction to a previous dose or severe allergic reaction to a vaccine component, immunodepression and moderate or severe acute illness.

Fernando Costa Silva, 2007 (last update: 2009)