Warning as winter viruses trigger deadly side effects up to 3 months after infection

WINTER bugs could raise the risk of deadly side effects up to three months after infection.

You could be up to five times more likely to suffer a stroke or heart attack in the weeks following a bout of flu or Covid-19, scientists suggest.

Meanwhile, viruses that linger in the body, such as the chickenpox bug that causes shingles or HIV, may also increase the risk of serious cardiovascular disease in the long term, the review of 155 scientific studies found.

It follows warnings of an early flu surge from UK health chiefs.

Kosuke Kawai, adjunct associate professor at the David Geffen School of Medicine at the University of California, Los Angeles, and lead author of the new study, said: “It is well recognised that human papillomavirus (HPV), hepatitis B virus and other viruses can cause cancer.

“However, the link between viral infections and other non-communicable diseases, such as cardiovascular disease, is less well understood.

“Our study found acute and chronic viral infections are linked to both short- and long-term risks of cardiovascular disease, including strokes and heart attacks.”

The research – published in the Journal of the American Heart Association – reviewed all published studies examining links between viral infections and non-infectious, long-term health issues like heart disease, narrowing it down to 155.

Some studies that compared people’s risk of cardiovascular disease in the weeks following a respiratory infection to their risk if they hadn’t had the infection at all.

Researchers’ analysis showed that patients were up to four times more likely to have a heart attack in the month following a flu infection.

For strokes, the risk rose to five-fold.

Meanwhile, people struck down by Covid were three times more likely to have both a stroke and heart attack in the 14 weeks – three and a bit months – afterwards.

But researchers said the risk could remain elevated for up to a year after infection.

They attributed this higher risk of heart disease after a winter bug to inflammation.

The immune system releases molecules that trigger and sustain inflammation to fight bugs.

These can make the blood more likely to clot, an effect which lingers after the infection passes.

Both inflammation and blood clotting can hinder the heart’s ability to function properly and may help explain the increased heart attack and stroke risk, study authors said.

Inflammation plays a key role in the development of cardiovascular disease, as it can encourage fatty deposits to form in arteries, which can trigger heart attacks and strokes if they rupture.

As a result, managing inflammation is becoming an important part of preventing and treating heart disease.

Some studies also looked at the long term effects of chronic viral infections on cardiovascular health.

They found that people with HIV had a 60 per cent higher risk of heart attack and 45 per cent higher risk of stroke in the long term.

Meanwhile, hepatitis C – a viral infection spread by infected blood – can up the risk of heart attack by 27 per cent and stroke by 23 per cent.

And people with shingles – caused by the varicella zoster virus – had a 12 per cent higher risk of heart attack and an 18 per cent higher risk of stroke compared to people without the infection.

When you get chickenpox, the virus stays in the body and can be reactivated later and to cause shingles if your immune system is weakened, for example by stress.

Shingles is a common infection.

Prof Kawai said: “The elevated risks for cardiovascular disease risks are lower for HIV, hepatitis C and herpes zoster than the heightened short-term risk following influenza and COVID.

“However, the risks associated with those three viruses are still clinically relevant, especially because they persist for a long period of time.

“Moreover, shingles affects about one in three people in their lifetime.

“Therefore, the elevated risk associated with that virus translates into a large number of excess cases of cardiovascular disease at the population level.”

The findings suggest that vaccinating against flu, Covid and shingles has the potential to reduce the overall rate of heart attacks and strokes.

Researchers cited a 2022 review, which found that flu vaccines could lower the risk of cardiovascular events by 34 per cent.

Another study published earlier this year suggested people given shingles jabs had a 3 per cent lower risk of heart attack or stroke.

Prof Kawai said: “Preventive measures against viral infections, including vaccination, may play an important role in decreasing the risk of cardiovascular disease.

“Prevention is especially important for adults who already have cardiovascular disease or cardiovascular disease risk factors.”

Early flu surge

The study comes after health chiefs in the UK warned that we may be hit by an early flu season.

The latest data show that flu activity is continuing to increase among school-aged children, with a top NHS nurse urging parents to get their children jabbed against flu this October half-term to prevent the virus “spreading like wildfire”.

“It is hugely concerning that flu has hit us early this year, with a worrying increase among children,” Duncan Burton, chief nursing officer for NHS England, said.

“The virus changes each year, so vaccination remains the best way to shield your child from getting seriously ill.”

Jason Murphy, Head of Pharmacy at Chemist4U, told Sun Health: “With flu season underway, it’s important to be aware of the early signs of the flu in children, as symptoms can develop quickly and can often be mistaken for a common cold.

“Parents should look out for symptoms like a high temperature, chills, muscle aches, tiredness, and loss of appetite.

“It’s also important for them to keep an eye out for some of the less obvious symptoms, like ear pain, stomach upset, or vomiting.

“These can be easily missed but are quite common in younger children with the flu.”

The pharmacist shared tips on protecting kids from the virus and how to prevent spread.

“The flu vaccine is the best protection, especially for children, who tend to spread the virus quickly in school and nurseries.

“Alongside vaccinations, you can help reduce the risk by encouraging regular handwashing, teaching kids to cover their mouths when coughing or sneezing, and keeping them at home if they’re unwell. 

“While masks aren’t routinely recommended for children in the UK, they may be useful in certain situations.

“For example, if the child is recovering and needs to be around vulnerable family members, or in crowded indoor spaces during flu season. 

“To manage symptoms and to help their children recover as fast as possible, it’s important they get lots of rest, drink plenty of fluids, consider Vitamin C supplementation and manage any pain with age-appropriate pain relief. 

“To stop the flu spreading within the home, make sure shared surfaces like door handles and remote controls are regularly cleaned, encourage everyone to use their own towels and cups, and open windows for better ventilation where possible.

“Even small steps like these can make a big difference in keeping the rest of the family flu-free.”