Vaccination remains the best way to prevent chickenpox, also known as varicella, a highly contagious viral infection that spreads mainly among children, although people of all ages can contract it. While the illness is mild in most cases, it can cause serious complications, particularly in infants, pregnant women and people with weakened immune systems.
How the infection spreads and the incubation period
The disease is caused by the varicella-zoster virus and spreads through the respiratory system, as well as through droplets from coughing and sneezing and tiny airborne particles, particularly in poorly ventilated indoor spaces. Infection can also occur through direct contact with the fluid inside blisters, or indirectly by touching contaminated objects and surfaces, such as toys and doorknobs, and then touching the face.
An infected person can transmit the virus to others about 48 hours before the rash appears and remains contagious until all open blisters have crusted over. The risk of infection is higher among people who have not previously been exposed to the disease or received the vaccine, as well as those taking immunosuppressive drugs and people with diseases that weaken the immune system, such as cancer.
Symptoms usually appear 10 to 21 days after exposure to the virus. A fever of 38 degrees Celsius or higher may occur one or two days before the rash, accompanied by headache, fatigue, malaise, loss of appetite and body or muscle aches. The infected person may also experience stomach discomfort.
A rash that progresses through three stages
An itchy rash is the most prominent sign of chickenpox. It may begin on the face, chest, back or scalp before spreading to the rest of the body. In some cases, it extends inside the mouth and throat, onto the eyelids and eyes, and to the genital area, as well as the tissues lining the urethra, anus and vagina.
Stages of rash development
Raised red or pink spots or bumps, known as papules, appear.
Within about a day, the papules develop into small, clear fluid-filled blisters known as vesicles, which may burst and leak fluid.
The blisters dry out and crust over before eventually healing and falling off.
Because new bumps continue to appear over several days, papules, blisters and scabs may all be present on the infected person's skin at the same time. The rash usually lasts between 5 and 10 days, while recovery takes about 7 to 14 days. The infection is generally mild in healthy children, while symptoms may be more severe in adults.
Managing the disease and possible complications
Healthy children usually recover on their own within one to two weeks, and management focuses on relieving symptoms and keeping the patient comfortable. Helpful measures include resting, drinking sufficient fluids, bathing in cool water, wearing loose-fitting clothes and trimming the fingernails to reduce scratching of the blisters and lower the risk of skin infections.
However, chickenpox can sometimes lead to serious complications, including dehydration, pneumonia and encephalitis. Bacterial infections can also affect the skin, soft tissue, bones, joints or bloodstream, and may develop into sepsis, or blood poisoning.
Possible complications also include toxic shock syndrome caused by certain types of bacterial infection, and Reye's syndrome, which causes swelling in the brain and liver and may affect children and adolescents who take aspirin while they have chickenpox. In very rare cases, the disease can lead to death.
An unvaccinated pregnant woman can transmit the infection to her baby, particularly late in pregnancy or during childbirth. This can cause the newborn to develop chickenpox, a condition requiring urgent medical care.
Chickenpox and shingles are linked to the same virus. After recovery, the varicella-zoster virus remains dormant in nerve cells and may reactivate years later, appearing as shingles. Therefore, anyone who has previously had chickenpox remains at risk of developing the condition later.
The vaccine and precautions before vaccination
The vaccine reduces the risk of chickenpox and its complications. Even if infection occurs after vaccination, symptoms are usually milder, with fewer blisters and a low-grade fever or no fever.
Vaccination is particularly important for people working in health care, education and child care, as well as international travelers, military personnel and adults who have contact with young children, in addition to women of childbearing age who are not pregnant. A blood test can be performed for people who do not know whether they have previously had chickenpox or received the vaccine.
The vaccine is not given to pregnant women, and anyone who receives it before pregnancy should wait at least one month after the final dose before attempting to become pregnant. A doctor should also be consulted before vaccination in cases of a weakened immune system, an allergy to the antibiotic neomycin, cancer treated with radiation or medication, or a recent blood transfusion or transfusion of one of its components.
