Wave of illness in San Diego kids

‘Staggering’ surge of respiratory infections signals an early, fierce flu season, experts say.

SAN DIEGO — Alarming surges of respiratory illness at a San Diego high school and the region’s only children’s hospital are strong evidence that a fierce flu season has arrived early this year.

About 1,000 of the 2,600 students at Patrick Henry High School in San Carlos were absent Wednesday; the majority were said to have gotten sick after homecoming weekend.

Hundreds of them, school officials told parents in a notice, tested negative for COVID-19, causing public health officials to say they suspect that the unprecedented outbreak was caused by the flu. Respiratory syncytial virus, or RSV, could also be playing a role.

Dr. Cameron Kaiser, a deputy public health officer for San Diego County, said his office is monitoring the outbreak because of its large size. No school has come close to seeing 40% of its student body call out sick during the COVID-19 pandemic.

The global public health community has warned for months that the U.S. may be in for a particularly severe flu season after serious bouts of influenza-related illness flooded hospitals in Australia during the Southern Hemisphere’s winter season.

“Seeing this in October is pretty staggering,” Kaiser said. “While the majority of kids are going to be just fine, you know, if we’re seeing flu outbreaks that large at a local high school, we’re probably seeing them in other places in the community.”

The region has reported 1,000 flu cases so far this season, which started July 1. The most recent week for which local data are available recorded 304 cases, Kaiser said, compared with a five-year average of 22.

And it’s not just cases of the flu that are spiking.

Rady Children’s Hospital is experiencing an unexpected increase in the number of kids arriving in its emergency department with runny noses, coughing, sneezing, fever and shortness of breath, officials said Wednesday afternoon.

These children are testing negative for the coronavirus but have, for the most part, been confirmed to have RSV, said Dr. John Bradley, director of Rady’s division of infectious diseases.

The virus is one of several that cause the common cold, though infection can be more severe in some, especially young kids.

Bradley said the hospital has admitted about 250 young children with RSV that has caused lower respiratory-tract infections that, in some cases, have turned into viral pneumonia, requiring treatment with supplemental oxygen.

RSV is highly contagious and is known to cause an increase in sick visits in the winter months, but such a fierce and early arrival is uncommon, Bradley said.

“I’ve been here for 34 years, and I’ve never seen this kind of volume in October,” he said. “This is like something we might see in January in the middle of an influenza epidemic.”

About 20% of children in Rady’s intensive care units Wednesday were admitted for severe breathing problems caused by RSV-related lung inflammation, Bradley said.

Those with more mild breathing problems, he said, receive supplemental oxygen for about two days, while those in intensive care tend to have chronic lung or neurological disorders that require additional “positive pressure” to reopen lung passages.

“All you need to do is give them oxygen and a little bit of pressure to help them expand their lungs, and they’re fine,” Bradley said, adding that less than 10% of children with RSV have needed intensive care.

The odds of a severe case of RSV are the highest with the first or second infections, he said. After the immune system has had a few chances to fight off the virus, symptoms become more cold-like for the rest of the person’s life.

As to why RSV has made such an early and fierce run among local children, a more aggressive strain of the virus may be circulating this year, Bradley said. But the COVID-19 pandemic, which kept young children home for the first few years of their lives, is also likely playing a significant role.

“If you look at it from a birth cohort standpoint, there are probably two or three times more susceptible children who’ve never had RSV in the community right now,” Bradley said. “When they get infected, they spread this to older siblings, so we’re admitting a lot of infants but also a lot of older kids with, say, asthma or some other underlying disease.”