Scientists in Israel identified six cases in a new study of patients developing a skin rash known as herpes zoster after receiving the Pfizer vaccine, according to a study in the Rheumatology journal.
Herpes zoster starts off as a small, itchy skin rash, but if left untreated, it could cause nerve damage and pain, the Jerusalem Post reported.
This can include a prolonged burning sensation on the skin even after the rash disappears.
Researchers from Tel Aviv Sourasky Medical Center and Carmel Medical Center in Haifa found those with autoimmune inflammatory rheumatic diseases had a higher risk of developing the herpes infection.
Out of 491 patients, six people or 1.2 percent experienced the infection, researchers said.
The six patients all have mild cases of autoimmune inflammatory rheumatic diseases and were young, though the infection is generally more common in those over the age of 50.
"That is why we reported on it," Dr. Victoria Furer, the lead author, told the outlet.
Five of them developed herpes zoster after the first dose and the sixth got it after the second.
But it’s still unclear whether the vaccine caused the cases of herpes zoster.
"We cannot say the vaccine is the cause at this point," Furer told the outlet. "We can say it might be a trigger in some patients."
Furer said further research is necessary and one implication could be that patients with autoimmune inflammatory rheumatic diseases be encouraged to get vaccinated against herpes zoster before getting their COVID-19 shot.
"We should not scare people," she told the Jerusalem Post. "The overall message is to get vaccinated. It is just important to be aware."