Dr Ronan Leahy MB
Consultant in Paediatric Immunology and Infectious Diseases Senior Clinical Lecturer in Paediatric Immunology Chair, Drugs and Therapeutics Committee Children’s Health Ireland (CHI) at Crumlin
Chickenpox, for most of us, is remembered as a nasty childhood itch lasting a few days and it’s gone. For a minority it’s more serious, even life-threatening, but a vaccine is available to protect this population.
Chickenpox is a common, preventable infection caused by the varicella-zoster (VZV) which, in the vast majority of cases, causes nothing more severe than an unpleasant itchy blistering rash. In certain vulnerable populations, however, it can cause more serious illness, even death. But this can be prevented by adoption of the vaccine against the varicella-zoster (VSV).
Signs and symptoms
Some 90% of adults in temperate climates have had chickenpox by the time they reach adulthood. Once a person is infected, and has recovered from chickenpox, the virus lies dormant in a person’s body, only to wake up when they experience sickness or stress as adults and cause painful shingles. It is transmitted from person to person either by direct contact with skin blisters or by inhaling tiny viral particles suspended in the air. It is one of the most contagious diseases that is known to medicine.
The chickenpox rash appears 10-21 days after exposure. The pox evolves from flat pink spots that blister with clear, then cloudy, fluid which then dry and crust. The rash is invariably very itchy. Other symptoms include fever, loss of appetite, headache and malaise.
The vast majority of people who get chickenpox will make a full recovery, but for certain vulnerable populations it can be a big problem. The groups at most risk include children and adults who need to take immunosuppressive medications for medical conditions such as arthritis or inflammatory bowel disease. If these patients contract the chickenpox virus, it can cause more severe disease that can damage the lungs, liver, or brain. Pregnant women are also at risk of severe disease, and the virus has the potential to damage the developing baby if infected in the womb.
The vast majority of people who get chickenpox will make a full recovery, but for certain vulnerable populations it can be a big problem.
Vaccine in Ireland
The VZV vaccine is licensed and marketed for use in Ireland. It is not yet part of the National Primary Immunisation Programme for all children in Ireland, but has been part of the vaccination schedule for all children in many countries such as Canada and the US. Parents can request it from their GP, however the cost for the vaccine and its administration is borne by the parent. The feasibility of Ireland adding the VZV vaccine to its national vaccine programme is undergoing evaluation.
The availability of a vaccine against the virus that causes chickenpox is great news for these vulnerable groups. Vaccinating all children early in life has the potential to protect the children themselves from both chickenpox and shingles. It also protects the children from severe disease if they subsequently need to take immunosuppressive medications. Furthermore, it prevents children from infecting vulnerable family members. The VZV vaccine is a live attenuated vaccine – or weakened form of the virus – and was first licensed for use in 1984.
The usage data has proven VZV vaccines to be highly immunogenic, efficacious and safe. Chickenpox vaccination protects approximately 86-98% of children and 75% of adolescents and adults.