Covid boosters increase risk of virus that harms brain health, new study finds

Scientists have found that the risk of shingles may increase slightly in the weeks following Covid vaccination.

The discovery came as researchers at the University of Groningen in the Netherlands analyzed the electronic health records of more than two million people aged 12 and over who had received at least one Covid vaccine.

The study found that the risk of developing shingles within 28 days after vaccination increased by seven percent when all doses were combined and increased by 21 percent after the third or booster dose of the mRNA vaccine.

Manifesting as a painful, blistering rash, shingles is caused by the varicella-zoster virus, which most people first encounter as chickenpox in childhood.

A separate study found that adults 50 and older who were hospitalized for shingles were seven times more likely to develop dementia.

Researchers found that among men of all ages, the risk of developing shingles was significantly higher after receiving a vector-based vaccine, with a 38 percent increase.

The authors noted that the increase in shingles risk after a booster dose of mRNA was small, transient, and limited to certain subgroups, and that most cases were treated in general practice rather than requiring hospitalization.

According to reports, the study comes as the FDA prepares plans to impose a ‘black box’ warning on Covid vaccines, the agency’s most serious warning about potential side effects.

A black box warning, which appears above the prescribing information, is placed on medications or vaccines to highlight major risks, such as serious side effects or restrictions.

The FDA’s move was disclosed to CNN by two people familiar with the matter who spoke on condition of anonymity because they were not authorized to speak to the media.

New study published in peer-reviewed journal Drug Safety On December 11, he suggested that shingles could occur after a Covid vaccine because important immune cells called lymphocytes may be temporarily depleted after vaccination, allowing the virus that causes shingles to awaken.

Repeated doses of the vaccine, especially a third booster, can make T cells less active for short periods of time, and T cells can help control viruses hiding in the body.

The researchers emphasized that this doesn’t prove the vaccine causes shingles, just a small, temporary link in some people.

Hong Kong reported a sharp increase in hospitalizations for shingles shortly after the Pfizer/BioNTech vaccination, the study noted.

However, a US study using healthcare claims data found no increase in risk after the Covid vaccine and the vaccine was not linked to a higher risk than the flu vaccine.

The team carried out the study in three steps, including analyzing all available Covid vaccines, including unknown brands.

The study found that the risk of developing shingles within 28 days after vaccination increased by seven percent when all doses were combined and increased by 21 percent after the third or booster dose of the mRNA vaccine.

Second, vaccines were separated by species, mRNA versus vector.

mRNA vaccines, such as Pfizer/BioNTech and Moderna, use genetic material in the form of mRNA to directly instruct cells to make the spike protein.

Vector vaccines, such as AstraZeneca or Johnson & Johnson, use a different virus modified so it cannot be replicated to carry instructions into cells. The team then analyzed the vaccines by brand.

It was difficult to determine which vaccine caused shingles in individuals who received two doses less than 28 days apart, so only those with a consistent vaccination regimen were included in type- and brand-specific analyses, according to the study.

The average age of the participants was 51 years old, with most people being in the 32-year-old average age range.

The two most common health conditions were cardiovascular disease, affecting 539,134 people (25.7%), and chronic lung disease, affecting 341,747 people (16.3%).

The majority of participants (54.6%), comprising 1,145,212 people, received two doses of the vaccine.

The most commonly administered vaccine was Pfizer/BioNTech, accounting for 69.2 percent of all doses, followed by Moderna at 18.6 percent.

A study published in April spanning more than two decades found that shingles can trigger early-onset dementia.

Importantly, the greatest risk was seen in people ages 50 to 65, which is younger than the typical age of people with dementia.

In the new study, Italian researchers recruited 132,986 adults aged 50 and over.

Of these, 12,088 were hospitalized with a diagnosis of shingles, which was called ‘herpes zoster disease’ in the study.

After just one year, the incidence of early dementia in the group with severe shingles doubled compared with the other two groups.