Masking and lockdowns weakened children’s immune systems, leading to increases in summer viruses: report

These children are being admitted with respiratory viruses usually seen during the winter months, with Thomas Murray, an infection-control expert and associate professor of pediatrics at Yale, telling the Washington Post that "That’s not typical for any time of year and certainly not typical in May and June."

Last month, Yale New Haven Children’s Hospital noted seven different respiratory viruses that children were being admitted with, with some children being admitted with two viruses, and a few having three.

These viruses included adenovirus, rhinovirus, respiratory syncytial virus (RSV), influenza and parainfluenza, as well as the still lingering coronavirus.

Michael Mina, an epidemiologist and chief science officer at the digital health platform eMed, explained that the sharp uptick in cases of these viruses outside of their usual seasonal occurrences was to be largely blamed on the lack of exposure to viruses over the last two years.

With regular contact with viruses, the human body develops immune system responses to combat future pathogens. This system has "enough memory to make it more like a good hearty booster than a bad infection," Mina said.

Mina explained that without this regular occurrence of coming into contact with viruses on a regular basis, it throws the immune system out of balance.

He said that with the social distancing and masking measures that were put into place, if a person goes too long without exposure, the system may reset itself and be unable to fight off a future infection.

According to the Washington Post, "That, Mina and others say, is what happened once people doffed their masks and started gathering indoors. Viruses began circulating out of season because population immunity was low even if other conditions for them were not optimal."

"All of these decisions have consequences," Murray said. "You do the best you can with the information you have."

What is occurring now is the hospitalization of people with viruses that may not have required hospitalization before.

Such is the case with rhinovirus, the cause of the common cold, which previously saw rare hospitalization cases.

"When people are getting colds, they do seem to be a little worse," said Richard Martinello, a specialist in respiratory viruses at Yale School of Medicine, though he emphasized that so far the evidence is mainly anecdotal.

The flu, which reemerged in December of last year after being largely non-existent the year before and disappeared in January corresponding with the surge of the omicron variant of COVID-19, has made an early summer comeback. Experts though note that this reemergence is without the common lineage known as Yamagata, which they say could have gone extinct after it was last seen in early 2020, or could be waiting to strike again.

"It’s a massive natural experiment," said Mina.

RSV mainly attacks children under the age of 5. The hardest-hit populations being prematurely born babies and other high-risk infants.

The virus made a reemergence last summer, and is already causing havoc in May and June of this year. The virus usually infects children between November and February.

Experts have noted that children born over the past two years may bring about interesting results, with these children barely being exposed to the normal number of viruses they usually would see in their early years.

According to The Washington Post, "The cohort of babies born over the past two years will yield a lot of information. Normally a child younger than 5 has on average a virus in his or her nose 26 out of 50 weeks of the year. Serious RSV and rhinovirus infections in those early years are associated with the development of asthma later in life."

"Those kids did not have infection at a crucial time of lung development," Foxman said, making them key to understanding the relationship between the viral infection and asthma.