German and University of Virginia researchers conducted a big retrospective cohort study. They compared the occurrence of shingles in people who received a COVID-19 shot and those who did not. The study found a significant difference, which suggests that there may be a connection between COVID vaccinations and increased risk of developing shingles or herpes zoster.
The authors stated that there have been reports of a link between getting the COVID vaccine and developing herpes zoster (HZ) globally. Their conclusion was that getting shingles after receiving the COVID vaccine may be a rare negative reaction, pointing out that the reactivation of varicella zoster (VZ), also known as chickenpox, is a well-known occurrence with infections and other vaccines.
The virus that causes chickenpox (VZ) can reactivate later in life as shingles (caused by the HZ virus). This results in a painful, blistering rash that appears on the skin's nerves. VZ, like other herpes viruses, remains dormant in the nervous system until reactivated.
Individuals who are 60 years old and above are at a higher risk of developing shingles, mainly if they don't come in close contact with children recovering from chickenpox infections on a regular basis. Post-herpetic neuralgia that can last from several months to years may affect approximately 20% of those who recover from shingles.
Shingles can be triggered by several factors, including aging, stress, drugs, and vaccines. Reports suggest that there has been a rise in cases of VZ virus reactivating after individuals have received COVID vaccines, particularly those that use mRNA technology like Pfizer/BioNTech's Comirnaty and Moderna/NIAID's Spikevax.
There is speculation among experts that the reactivation of varicella zoster following COVID vaccinations may be due to changes in the immune system. It is known that risk factors for developing shingles include advanced age, experiencing significant stress, and having a weakened immune system.
The Study Included Both Individuals Who Received COVID-19 Vaccinations and Those Who Did Not, Encompassing a Large Population
The study analyzed data from 1,095,086 people who received the COVID vaccine and 16,966,018 people who did not receive the vaccine but went to a clinic, using the TriNetX Global Health Research Network database. The database combines information from different healthcare centers across 19 countries and the individuals were chosen to have similar age and gender. The vaccinated group went to the clinic to receive the vaccine, while the unvaccinated group had a different reason for their clinic visit.
A study showed that the likelihood of getting shingles within 60 days of a clinic visit was 20% for those who received the COVID vaccine, while it was 11% for those who did not. The authors of the study noted that there was a statistically significant difference between the two groups.
The authors found that there was a higher rate of people getting herpes zoster (HZ) after receiving the COVID-19 vaccine, which supports their hypothesis. This suggests that HZ could be a rare but possible side effect of getting vaccinated for COVID-19.
An Infection With Sars-Cov-2 Can Also Lead to the Development of Shingles
Recent case reports suggest that the SARS-CoV-2 virus can cause shingles in addition to its known effects on the lungs and heart. It appears that the virus can reactivate the VZ virus, possibly due to the stress on the body from fighting the SARS-CoV-2 infection, as some researchers have hypothesized.
In 2022, a study was published in the journal Open Forum Infectious Diseases comparing 400,000 individuals who had contracted SARS-CoV-2 to 1.6 million individuals who had not. The study found that adults over 50 who had contracted SARS-CoV-2 had a 15% higher risk of developing shingles within six months. Furthermore, individuals who had severe COVID cases requiring hospitalization had a 21% risk of developing shingles.
A New Study Suggests That Shingles Could Be a Possible Side Effect of COVID-19 Vaccinations
In 2021, Israeli researchers published a study in the British Society of Rheumatology that suggests shingles may be a possible side effect of COVID vaccines. The study analyzed adverse events in individuals with autoimmune inflammatory rheumatic disease (AIIRD) who received a COVID vaccine, and compared 491 AIIRD patients to 99 healthy subjects. The study was conducted at two rheumatology departments in Israel.
Out of the female subjects in the AIIRS group, 6 of them developed shingles after vaccination, which is 1.2% of the group. In comparison, no subjects in the control group developed shingles. Among the 6 women in the AIIRS group who developed shingles, 5 of them got it after the first COVID shot and one after the second dose. However, all of the shingles cases were mild and resolved within six weeks.
The Occurrence of Shingles Was Observed in Patients Who Have Been Vaccinated With Three Different COVID Vaccines
Three case studies of patients (one man and two women) who developed shingles between three to 13 days after receiving different types of COVID-19 shots were recently published in the Family Practice journal.
All three patients were between 67-79 years old, were overweight or obese, and had hypertension and dyslipidemia (abnormal amount of lipids in the blood) in their medical history.
A patient who had previously recovered from a SARS-CoV-2 infection did not develop shingles after receiving a COVID shot, even though other patients who received different types of COVID shots did develop shingles after the first dose. The COVID shots used were Comirnaty, Spikevax, and AstraZeneca/Oxford University’s Vaxzevria, and all patients completed the three-dose series. The study authors suggest that “an altered immune landscape involving cellular immunity might be implicated in this phenomenon.”
Vaccination May Cause a Decrease in Immune System Function and Enable the Reactivation of the Varicella Virus
In May 2022, a study examined 10 instances of shingles that developed one to three weeks after receiving the COVID vaccine. The study authors suggested that temporary changes to the immune system after vaccination may lead to the reactivation of the herpes zoster virus, as seen in COVID infections. They suggested that a decrease in counts of certain immune cells, specifically CD4+ T cells, CD8+ T cells, and natural killer cells, could increase the risk of shingles reactivation and development.
Shingles can lead to various complications, such as postherpetic neuralgia (lingering pain); eye-related issues like ophthalmicus (painful rash near the eye), acute retinal necrosis (tissue death), and Ramsay Hunt syndrome (facial paralysis and hearing loss); facial or limb paralysis due to Bell's palsy or Guillain-Barré syndrome; brain or spinal cord inflammation (encephalitis, aseptic meningitis, or myelitis); nerve damage that affects muscle control (peripheral motor neuropathy); and bacterial skin infection.
The authors of the study mentioned that activating the herpes virus is a rare side effect that can occur with other vaccines, such as those for influenza, hepatitis A, rabies, Japanese encephalitis, and yellow fever. Although there is limited research, it is probable that the COVID-19 vaccines may also cause this complication. The study authors cautioned that this might happen.
With the ongoing COVID-19 vaccination campaigns, there is a concern that a significant number of elderly individuals may experience negative consequences due to a potential causal link. This is because there will be a large number of people vaccinated, and the impact could be devastating for them. It is important to have procedures for post-marketing surveillance and continuing evaluations of vaccination safety to identify any potential risks and take necessary steps to mitigate them for vaccinated individuals. Our research highlights the need for additional investigation into the possible connection between COVID-19 and herpes zoster when administering vaccines to older adults and/or those with weakened immune systems.
A Reduction in the Number of Lymphocytes May Be a Contributing Factor to Developing Shingles After Receiving a Vaccination
Lymphopenia is a condition caused by COVID in which the body doesn't have enough white blood cells, specifically lymphocytes, to fight off infections. This can cause symptoms such as swollen lymph nodes, spleen, and joints, fever, skin rash, and frequent infections or difficulty healing from infections. CD4+ and CD8+ lymphocytes are most affected, and this T-lymphocyte impairment could result in shingles.
According to the Pfizer/BioNTech COVID vaccine trial data, after receiving the vaccine, there was a decrease in lymphocytes count in the initial days, which was directly proportional to the dosage administered. As per the trial results, around 46% of the study participants experienced a temporary drop in lymphocytes count to below 1×10.9. Based on these findings, the researchers inferred that the dormant VZ virus in the body may get reactivated during the period of lowered lymphocyte counts.