A new study questions the notion that reexposure to chickenpox in adulthood completely prevents the development of herpes zoster, or shingles.
The new findings show that while the chicken pox risk drops significantly, full immunization is unlikely.
As a result, the researchers call for a reappraisal of childhood vaccination policies.
Herpes zoster is a viral infection that occurs when the chickenpox virus becomes reactivated after lying dormant in the body.
The herpes zoster infection is also known as shingles, and the chickenpox virus is also called the varicella virus.
According to a theory, among people who had chickenpox as children, reexposure to the varicella virus in adulthood stops shingles from reoccurring.
In other words, the belief is that reexposure boosts immunity in adults.
Dr. R. Edgar Hope-Simpson first formulated this theory in 1965, and other scientists, who have later adhered to it, call it the “exogenous boosting hypothesis.”
As a result of widespread support for this theory, several countries do not offer routine chickenpox vaccination for children.
The concern is that reducing the prevalence of chickenpox would limit the protective effects of reexposure during adulthood.
It increases the rates of herpes zoster infection and shifting the burden on to older populations.
Another reason that some countries — such as the United Kingdom — avoid routine vaccination is that it is considered a “mild” childhood disease.
Meanwhile, herpes zoster can cause severe complications.
In 2014, the World Health Organization (WHO) reported that the infection led to 4.2 million hospitalizations around the world annually.
Furthermore, new evidence suggests that this immunity boost is not as strong as scientists once believed.
Chickenpox, a very contagious infection caused by the varicella-zoster virus.
It mainly affects kids, but adults can get it, too.
The telltale sign of chickenpox is a super-itchy skin rash with red blisters and generally found mild, especially in children.