RSV: Pandemic ‘immunity gap’ may be behind rise in respiratory cases, scientists say



CNN

The measures that have helped keep us safe from Covid-19 over the past 2½ years — lockdowns, physical distancing, wearing masks, washing hands — have also helped control the spread of other viruses. As people go to school and work and take off their masks, viruses including respiratory syncytial virus and the flu are back in full force.

That “immunity gap” from the last few years is probably behind us “unprecedented” Early rise RSV This year’s infections, scientists say – it blew Other seasonal respiratory viruses Out all around the world.

“For as long as we’ve had a record of RSV and other respiratory diseases in the United States, there have been these regular outbreak patterns,” he said. Rachel Baker, is an epidemiologist and assistant professor at Brown University.

“RSV appears every year in the late fall/winter and often has these outbreaks in young children. Then it disappears again in the spring/summer months and reappears the following winter,” Baker said. “It’s very routine and predictable.”

Until it isn’t.

RSV cases began in the United States is shown in the spring and is now 60% higher than the peak week of 2021, A CNN analysis shows that number is probably lower.

Across the United States, flu cases are on the rise And increasing A little earlier than usual. A A few schools There has been a large absence, and medical offices say more people are sick Other respiratory viruses Sometimes it doesn’t fit Regular shapes.

Similar unusual patterns exist in respiratory infections such as Adenovirus, parainfluenza and rhinovirus Other countries too.

Scientists believe that the pandemic’s unprecedented actions have had unprecedented consequences.

“The scale of societal changes brought about by the Covid pandemic is truly unprecedented in modern times,” he said. Dr. Kevin MessagarAssociate Professor in the Department of Pediatrics at Children’s Hospital Colorado.

Like Covid-19, RSV and the flu are spread through droplets released into the air when people cough or sneeze. Drops can linger for hours on frequently touched surfaces like doorknobs and light switches.

So people who washed and disinfected their hands, wore masks and kept their distance from others did more than prevent the spread of the coronavirus.

“Those interventions, while best at controlling the spread of Covid-19, did a good job of controlling the spread of RSV and other respiratory diseases. cold feverBaker said.

The 2020 and 2021 seasons saw a sudden drop in RSV cases and hospitalizations. Studies have shownas well as Unusually modest Seasons of fever.

“It was really striking,” Baker said.

But once Covid-19 vaccines and treatments became available, more people began to return to school and work and socialize without masks. They also started sharing germs. Epidemic behaviors are called “immunity gap” or “Immunity loan” This makes more people in the US susceptible to diseases like RSV.

Children develop natural immunity when exposed to viruses. Most children catch RSV before age 2. US Centers for Disease Control and Prevention He says. Some are available for newborns Passive protection From mothers who pass antibodies through breast milk.

But for a year or two, babies born during epidemics or those around them have no chance of catching RSV or other viruses. Their immunity is reduced or not developed at all. So when those young children and their parents start interacting with other people, they are more likely to get sick.

“Decreased exposure to domesticated viruses created an immunity gap — a gap between evading infection and a lack of pathogen-specific immunity to protect against future infections,” Messager and Baker wrote in a commentary published this summer in the journal Medicine. The Lancet.

Because of this gap, they warned hospitals to be flexible and prepare for unpredictable respiratory illnesses..

“We know it’s inevitable that these diseases will come back,” Messacar told CNN.

The commentary warned of an influx of epidemics involving older children and newborns who were not exposed to the viruses.

“Now we’re seeing it spread pretty well,” Baker said. “And it doesn’t just strike babies, it usually strikes with that first birth cohort. It creates an epidemic in older children.

“That’s how infectious diseases work,” he added. “If you have more cases, they create more cases, and you get this spike.”

Baker and Messager don’t think this early-season pattern with RSV is permanent, but it could take some time to return to its predictable cycle.

“We’re in a little bit of a strange period right now, but I think in the next few years, we’ll start to see those regular outbreaks — well, depending on what’s going on with Covid,” Baker said. If the coronavirus gets bad enough to require more lockdowns, it could throw off the seasonality of other viruses again.

With viruses like the flu, there are more variables, Mesagar said.

There is no vaccine to prevent RSV, but there is a vaccine for the flu, so the flu shot is a good match for the strain in circulation and if enough people get it, the country could avoid an increase in cases of RSV like the one we have now.

Scientists are working on an RSV vaccine, but it may not arrive in time to help this season.

In the meantime, there are a few things you can do to control the spread of RSV, and they can be very familiar.

Wash your hands. Keep frequently used surfaces clean. Sneeze or cough into a tissue or into your elbow rather than your hands. Boost your immune system by getting more sleep and eating a healthy diet. Wear a mask, especially when you are sick. And most importantly, if you are sick, stay home.

“All of these non-drug interventions clearly work, and the more we can do to reduce any of these viruses, the better,” Baker said.

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