On your daily trudge through social media, you may have come across a headline saying something along the lines of “herpes possibly linked to COVID-19 vaccine.” Other news reports have suggested that herpes may be a “new side effect” of the COVID-19 vaccine.
Rest assured, there’s no risk of any COVID-19 vaccine giving you herpes, but the reports do highlight some important tidbits about vaccines, the immune system, and the strange world of herpesviruses.
The sensational new stories are based on a legitimate paper, recently published in the journal Rheumatology, in which researchers in Israel detail six women with autoimmune inflammatory rheumatic diseases (AIIRD) who developed herpes zoster shortly after receiving the Pfizer-BioNTech vaccine.
Better known as shingles, the condition is an infection caused by the varicella-zoster virus that presents a painful rash. First, it’s misleading to refer to shingles simply as herpes, which immediately drums up an image of oral and genital herpes infections seen in sexually transmitted diseases. While both infections are caused by members of the broad herpesvirus family, the infections that cause cold sores and genital sores are caused by herpes simplex virus 1 and 2, not the varicella-zoster virus.
None of the patients had ever developed shingles before in their life, but this isn’t to say the vaccine infected them with the virus. The varicella-zoster virus responsible for shingles is the same pathogen behind chickenpox. If you’ve had chickenpox at some point in your life, the varicella-zoster virus is now quietly lying dormant inside your nervous system. The infection can spring back to life in the form of shingles, however, if your immune system becomes weakened because of stress, other illnesses, etc. Vaccines, too, can put a mild strain on the immune system, which is why some people feel a bit under the weather after getting a jab. COVID-19 itself may even trigger shingles because the varicella-zoster virus takes advantage of the compromised immune system.
The researchers note that the study design was not structured to determine a causal relationship between vaccination and shingles, so it’s not possible to concretely say how the two factors are linked. Many experts have previously speculated there is no causal link at all and the association is mere coincidence.
After all, it’s also well-established that people with AIIRD are at a heightened risk of a shingles outbreak. Indeed, some of the patients in this new study were taking immunosuppressant drugs to temper their overactive immune system, which could potentially leave them vulnerable to the varicella-zoster virus. Even among the general population, shingles is incredibly common: almost 1 in 3 people in the United States will develop shingles in their lifetime, according to the Centers for Disease Control and Prevention. As such, it might not even be considered a surprise that just six predisposed people experience shingles at some point after getting their jab.
While the link between COVID-19 vaccination and shingles is certainly something scientists should investigate further, it’s a safe bet to say the issue is not as severe as some headlines have made out.
“We cannot say the vaccine is the cause at this point,” lead author Dr Victoria Furer, from the Tel Aviv-Sourasky Medical Centre, told The Jerusalem Post. “We can say it might be a trigger in some patients.”
“We should not scare people,” she continued. “The overall message is to get vaccinated. It is just important to be aware.”