The chickenpox virus, known as varicella-zoster virus, is one of the eight known herpes viruses that can infect human beings. After people contract and recover from chickenpox, usually at an early age, they gain lifelong immunity to the virus.
The first study to see the correlation between COVID-19 vaccinations and chickenpox comes from Israel. This study, published in the peer-reviewed monthly medical journal Rheumatology, looked into six women who had autoimmune disorders. They all developed shingles three to 14 days after receiving the first or second dose of Pfizer’s mRNA COVID-19 vaccine.
“To our knowledge, there were no reports of varicella-like skin rash or HZ in the mRNA-based vaccines COVID-19 clinical trials and our case series is the first one to report this observation in patients within a relatively young age,” the authors of the study wrote.
In Taiwan, researchers published in the peer-reviewed medical journal QJM a different case involving three healthy men – two older adults and one senior citizen – who developed shingles between two to seven days following the first dose of Moderna’s mRNA vaccine or AstraZeneca’s viral vector vaccine.
The researchers noted that HZ is not known to get reactivated following the administration of any other vaccines, but their study established the link between COVID-19 vaccines and shingles emergence.
The Taiwanese researchers are certain of the link due to the short delay between vaccination and emergence and the fact that the three patients they studied had healthy immune systems prior to the vaccination.
According to the researchers, vaccinated individuals who received a COVID-19 vaccine had a “statistically highly significant” chance of getting shingles, especially compared to the unvaccinated.
“Reactivation of the varicella-zoster virus appears to be a potential [adverse drug reaction] to COVID-19 vaccines,” wrote the authors. They added that “vaccination against COVID-19 seems to potentially raise the risk of precipitating HZ.”
Researchers warn of COVID-19 vaccine dangers
The authors of the Israeli study are hoping that they could raise awareness of the causal link between COVID-19 vaccines as a trigger for HZ, especially in young people with autoimmune inflammatory rheumatic diseases (AIIRD).
“Further vigilance and safety monitoring of COVID-19 vaccination side effects is warranted. Clinical registry of the safety of COVID-19 vaccination among patients with AIIRD will provide further insight into this open question,” wrote the Israeli authors.
The authors of the Taiwanese study noted that they have seen an increasing number of reports associating HZ to the mRNA COVID-19 vaccines, and that their study was the first to establish the link between shingles and a non-mRNA based COVID-19 vaccine like AstraZeneca.
“It invites the urgent need for more studies to investigate the particular mechanism behind this phenomenon and identify the risk factors,” they wrote.