RSV and Strep A: Are Kids Getting Sick After COVID Lockdowns?

RSV cases in the U.S. are soaring, with over three times as many cases being reported each week in November compared with the same period last year. In the U.K., an outbreak of Strep A has led to the deaths of 15 children, with a "steep increase" in cases of scarlet fever, which is caused by Group A strep bacteria, compared to what would be expected at this time of year, the government said.

Since 2020, multiple childhood illnesses have been attributed to a lack of exposure to common viruses during COVID lockdowns. In July, scientists suggested a mystery outbreak of hepatitis among children may have been down to them not being exposed to two common viruses. In October, Seattle Children's Hospital said an unusually high number of children were suffering from respiratory issues, KIRO 7 reported. Dr. Indi Trehan, from the hospital, told the outlet this may relate to "immune amnesia" from not having "low grade exposure to viruses."

Could the surging cases of RSV and Strep A cases also be the result of COVID lockdowns?

What Is RSV and Is It Airborne?

Thousands of children get sick with respiratory syncytial virus (RSV) each year, with infections starting to increase during the cold fall and winter months. However, this year, CDC data shows that cases began to spike in the summer. In November, the U.S. saw between 14,000 and 19,000 cases each week: in November 2021, there were only around 4,000 cases per week. Europe is also currently experiencing an early and high rise in RSV.

RSV is a common respiratory virus. It usually causes mild, cold-like symptoms, but can be more serious in infants or the elderly. CDC data shows that RSV is the most common cause of bronchiolitis (inflammation of the small airways in the lung) and pneumonia (infection of the lungs) in children younger than one in the U.S. However, most children get a mild RSV infection before they are two years old.

The virus is spread via respiratory droplets, being transmitted through coughs or sneezes similarly to cold, flu and coronaviruses. Symptoms include a runny nose, decreased appetite, a cough and a fever, and can begin around 4 to 6 days after infection.

Why Are RSV Rates Up?

"The 'hygiene hypothesis' argues that exposure to viruses and bacteria early in life 'trains' our immune system," Annette Regan, an assistant professor in epidemiology at the University of San Francisco–Orange County Campus, told Newsweek. "Without this training, it starts to malfunction and we see the development of immune dysfunction and disorders, like autoimmune diseases, allergies, and asthma."

In essence, the hypothesis claims that kids need to be exposed to bacteria and viruses in order to develop healthy immune systems, and that those who are not may be more prone to developing allergies or get more sick in the future. There is little evidence to support this idea, however, with multiple studies concluding that the theory is outdated. One review from 2016 published in the journal Perspectives in Public Health found that the original hypothesis was flawed, as "relevant microbial exposures are almost entirely unrelated to hygiene as the public understands it." Households that the originator of the theory had assumed were more hygienic and therefore less occupied by bacteria and viruses were in fact just as populated by microbes as others.

"The hygiene hypothesis ... is not at play here," Rebecca S.B. Fischer, an assistant professor in epidemiology and biostatistics at Texas A&M University, told Newsweek. "COVID prevention and mitigation strategies, even including 'lockdowns', mask wearing, and isolating while sick, did not create sterile environments, nor do good hygiene practices. So, to bring that concept into the current discussion demonstrates a misunderstanding of it."

Jack Feehan, an immunology researcher at Victoria University in Australia, also told Newsweek the idea that lockdowns stunted the immune system is not based around facts. "The immune system is not like a muscle, it does not weaken with disuse—generally the opposite in fact. This is borne out of the 80's concept of the hygiene hypothesis, which actually centered on families with fewer children (i.e. 'cleaner') having more allergies—but this has been almost entirely disproven."

Strep A UK Outbreak

Other illnesses, such as bacterial infection Strep A, are also seeing a surge in cases this winter.

Strep A, or Streptococcus pyogenes, can cause illnesses like strep throat and scarlet fever. These may present with symptoms like swollen neck glands, loss of appetite, nausea or vomiting and a red rash. Mild cases will often clear up on their own or after treatment with antibiotics.

In more severe cases, infections may be invasive group A Streptococcus (iGAS) infections, which can lead to much more serious illnesses like meningitis, necrotising fasciitis, Streptococcal toxic shock syndrome, and even death. However, iGAS infections are very rare.

Government data from the U.K. shows that a total of 4,622 cases of scarlet fever were reported in a 10-week period in England, with 851 cases in a single week. The average over the previous five-year period was 1,294 cases during the 10 weeks at this same period of the year.

Cases of iGAS, the more deadly version of the infection, have also increased this season, with 509 iGAS cases reported in England in the same 10-week period, compared with an average of 248 cases for the same period over the previous five years.

Additionally, five deaths in children under 10 years of age have been recorded within seven days of an iGAS infection diagnosis. The previous highest number of deaths during this period was during 2017, where 4 deaths were recorded.

The rise in Strep A cases may be for the same reasons as the rise in RSV cases.

Are Children Getting Sick From COVID Lockdowns?

COVID lockdowns did not stunt the immune systems of children as per the hygiene hypothesis, but it did prevent them from being exposed to the respiratory viruses and bacteria that they would have been pre-COVID.

"Now that we have been slowly re-entering normal life over the last year and half, these viruses and bacteria are more than happy to fill in these gaps [in infections] and since children skipped these previous normal exposures, they have limited immunity built up to protect them," Regan said.

RSV cases started increasing earlier than normal this year. This may be due to the lifting of COVID-19 protection measures, exposing children to illnesses that they normally might have already experienced.

"Immunity debt is a possible explanation—the idea that we are just experiencing a backlog of serious childhood infections," Matthew Woodruff, a human immunology researcher at Emory University, told Newsweek.

"I've talked to physicians that believe that the majority of current hospitalizations would have occurred anyway, but they have been delayed by a year or two due to lower circulation/personal contact. Worldwide lockdown wouldn't just impact the flow of COVID, it would impact the normal circulation of all of these viruses as well."

These cases could be more severe because kids are frequently being hit by multiple viruses at once.

"I can tell you as the parent of the young kids that got crushed at the beginning of October that they are sometimes getting sick with a new virus well before the previous one has cleared fully," Woodruff said. "What does it look like when you're on the back end of a mild COVID infection and then you get RSV? What happens when you are co-infected with Flu and rhinovirus? We know that immune responses are deeply impacted by pre-existing inflammation—is that in play here? Is there an existing SARS-CoV-2 reservoir in some recovered kids—and adults—that alters future immune responses?"

Sweden is also experiencing a surge in cases of RSV. Sweden did not impose nationwide lockdown measures during the pandemic, which may disprove the idea that lockdowns are responsible for the RSV surge.

"Whilst Sweden didn't have the same type of lockdowns, they did practice social distancing, were encouraged to stay home if unwell and masks were recommended in all crowded public spaces etc, so they would also have seen disruption to normal disease transmission patterns," Catherine Bennett, an epidemiology professor at Deakin University, told Newsweek.

"That said, there is European data showing RSV was on the rise pre-pandemic so there are probably a few things driving this surge, and it's hard to work out how much the pandemic—transmission disruption or the impact of recent COVID infection itself—might be contributing to this, and more research is urgently needed given the potential for the very young and the elderly to end up in hospital in more severe infections," Bennett said.

Strep A cases in the U.K. have also been linked to COVID lockdowns. The U.K. Health Security Agency is examining whether decreased immunity has played a part in the rise in cases.

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