By Jennifer Hassan & Adela Suliman

A rare, invasive form of a usually mild and common bacterial infection has killed several children in the United Kingdom in recent weeks, according to public health authorities, prompting alarm among parents and vulnerable adults.

There have been seven confirmed deaths in England and one in Wales caused by the Group A streptococcus bacteria, also known as Strep A, a spokesman for the U.K. Health Security Agency (UKHSA) said on Tuesday. British media say the death toll may be higher.

Strep A is highly contagious and commonly carried by many of us in our nose and throats and on our skin without resulting in serious illness, medical officials and experts say. While most cases are not life-threatening, it can develop into an infection known as invasive Group A strep (iGAS), which can be fatal, with the risk greatest among children and the elderly.

What is Strep A and the invasive infection it can cause?

Strep A refers to the Group A Streptococcus bacteria, which can cause numerous infections. Cases are often mild, but serious infections can come from the invasive Group A strep, known as iGAS, according to the UKHSA.

IGAS is rare, but it can be life-threatening. It occurs when bacteria goes deeper into the body, infecting the lungs, muscles and bloodstream.

“Whilst iGAS infections are still uncommon, there has been an increase in cases this year, particularly in children under 10 and sadly, a small number of deaths,” the UKHSA said in a statement this week.

What are the symptoms of Strep A?

Strep A symptoms are often flu-like and mainly include a sore throat sometimes called “strep throat.” In general, strep throat is a mild infection but can be very painful, according to the Centers for Disease Control and Prevention, and it usually takes two to five days for someone exposed to the bacteria to become ill. People can get strep throat more than once; getting it does not protect someone from contracting it again in the future.

Other symptoms can include a fever, headache, swollen lymph nodes in the front of the neck, nausea and skin infections such as pus-filled blisters or inflammation, according to Britain’s National Health Service.

It can also lead to illnesses such as tonsillitis, scarlet fever and cellulitis, according to the UKHSA. “While infections like these can be unpleasant, they rarely become serious,” it added. Most people with Strep A recover without any complications, it said.

By contrast, a cough, runny nose, hoarseness in the throat and conjunctivitis (also known as pinkeye) normally suggest a viral infection and not Strep A, the CDC says.

However, the more invasive iGAS infection can get into a person’s bloodstream and deep tissue, causing more severe illnesses such as blood infections, endocarditis (an infection of the heart’s inner lining), meningitis, urinary tract infections and streptococcal toxic shock syndrome, which causes low blood pressure and injury to organs such as the kidneys, liver and lungs.

How is Strep A transmitted?

Streptococcal bacteria is spread by person-to-person contact through coughing, kissing, sneezing and touching, from someone with an infection or a carrier, according to the NHS. Outbreaks are more frequent in facilities like schools and care homes where close contact is common, it said. Occasionally, the bacteria can also enter the body through food contaminated with it.

However, invasive streptococcal infections are more likely to be picked up by people with existing health conditions “that reduce immunity to infection,” the NHS says. For example, people with chronic illnesses including cancer, diabetes, kidney disease and those who use medications such as steroids may be “at greater risk” of the invasive form.

Why are children badly impacted?

“Rates of iGAS are highest at extremes of age — in children and the elderly,” said Michael Marks, an associate professor at the London School of Hygiene & Tropical Medicine. “This is not fully understood but may reflect immunity.” Children are also likely more exposed to Strep A at schools and other similar places, he added.

Simon Clarke, associate professor in cellular microbiology at Britain’s University of Reading, agreed that children tend to have less developed immunity and therefore could be more prone to picking up the infection.

Clarke added that the coronavirus pandemic might be a factor in the uptick of cases. “It may be the case that because of social distancing and lockdown, we’ve been exposed less to these sorts of bugs, and therefore there is less immunity in the general population and they transmit more frequently,” he said.

Cases of Strep A are currently “higher than expected” in the U.K. compared with previous years, according to the British government, with the UKHSA saying this week that investigations are underway into the increase among children under 10. “It isn’t possible to say for certain what is causing higher than usual rates of these infections,” it said. “Currently, there is no evidence that a new strain is circulating.”

Is there a Strep A vaccine?

There is currently no Strep A vaccine available. However, most cases are treated with a course of antibiotics.

Rapid tests and throat cultures, which involve swabbing, are most commonly used to diagnose Strep A, according to the CDC. Antibiotics should decrease the symptoms and prevent the bacteria from spreading to others, it said, making those infected “start feeling better in just a day or two” after beginning the drug.

Streptococcal infections can also sometimes be diagnosed by a blood or urine test, and invasive forms may need intravenous antibiotics, the NHS said. “Early treatment improves the outlook greatly,” it added.

“Strep A is theoretically vaccine preventable, and there are large efforts ongoing to help develop vaccines,” said Marks, who is running studies on transmission of Strep A and immunity in Gambia, with a view to supporting the development of vaccines. “In the long term, this strategy will hopefully reduce the risk of infection and death causes by Strep A worldwide.”

How can you or your child avoid getting Strep A?

Parents should look out for the symptoms above in their children and contact a health professional for advice if their child is very sick, not eating, dehydrated or has a dry diaper for over 12 hours.

“As a parent, if you feel that your child seems seriously unwell, you should trust your own judgement,” Britain’s government advised last week.

To prevent contracting the bacteria, the NHS suggests “good hand washing,” especially after coughing and sneezing, before preparing foods and before eating. Cuts and other wounds should also be kept clean and watched for signs of infection.

Teaching your child how to wash their hands properly with soap and warm water for 20 seconds, using a tissue to catch coughs and sneezes, are also useful to limit the spread. Putting used tissues in the trash, using alcohol-based hand sanitizer and washing plates and utensils of sick people are other measures that can be taken, the CDC said.

Most cases of Strep A infections normally resolve if caught early and are “treatable,” Clarke said.