Chickenpox, known medically as varicella, is a highly contagious viral illness caused by the varicella-zoster virus (VZV), a member of the herpesvirus family. Before the widespread availability of the vaccine, it was a common childhood disease, with most individuals contracting it at a young age. For those who have never experienced chickenpox, understanding the implications of this viral infection is important, especially given its distinct characteristics in adulthood.
Risk of Infection and Severity in Adulthood
Individuals who have not previously had chickenpox or been vaccinated remain susceptible to the virus if exposed. The varicella-zoster virus spreads easily through airborne droplets from coughs or sneezes, and direct contact with rash blisters. Up to 90% of non-immune individuals in close contact with an infected person will become infected.
Chickenpox is more severe in adults than children, often involving a more extensive rash, higher fever, and intense itching. Symptoms can include a widespread rash that begins on the chest, back, and face before spreading across the body, accompanied by fever, headache, tiredness, and loss of appetite. The illness typically lasts five to seven days, with new blisters appearing for up to five days.
The contagious period begins one to two days before the rash appears and continues until all blisters have crusted over. This means an infected person can spread the virus even before symptoms are fully visible.
Potential Complications for Adults
Adults contracting chickenpox face a higher risk of serious medical complications compared to children. Common complications include secondary bacterial skin infections like cellulitis, impetigo, or erysipelas, which can lead to scarring. These infections occur when bacteria enter broken skin from blisters.
Pneumonia, either viral or bacterial, is another serious risk for adults with chickenpox. This respiratory complication can be severe and carries a mortality risk if untreated. Encephalitis, an inflammation of the brain, is a rare but serious neurological complication that can also occur.
Cerebellar ataxia, involving impaired coordination, can develop in some cases. In rare instances, Reye’s syndrome, a serious condition affecting the liver and brain, may occur if aspirin is used to treat fever. Pregnant individuals and those with weakened immune systems, such as people undergoing chemotherapy or living with HIV, are at an even higher risk for severe complications.
Preventing Chickenpox
Vaccination is the most effective method for preventing chickenpox. For adults who have never had chickenpox or been vaccinated, two doses of the varicella vaccine are recommended, typically administered at least 28 days apart.
Vaccination reduces the risk of contracting chickenpox and, if infection occurs, typically leads to a milder illness with fewer symptoms. Since its introduction, the vaccine has reduced the incidence of chickenpox cases. Beyond vaccination, avoiding direct contact with infected individuals can help prevent transmission, especially during the contagious period.
No Risk of Shingles
Shingles, medically known as herpes zoster, is a distinct condition caused by the reactivation of the same varicella-zoster virus that causes chickenpox. After an individual recovers from chickenpox, the virus does not leave the body but instead lies dormant within nerve cells. Shingles develops when this latent virus reactivates later in life.
Therefore, individuals who have never contracted chickenpox cannot develop shingles. Without a prior chickenpox infection, the varicella-zoster virus is not present in their body to reactivate.