San Francisco Chronicle - (Sunday)
Winter worries as 3 viruses converge
In the past two years, practices such as social distancing and masking against the coronavirus served also to suppress other respiratory viruses that usually rear their heads in the colder months.
This season is off to a different start. Influenza and respiratory syncytial virus, or RSV, cases are rising earlier than normal in the U.S., already testing pediatric hospitals in some regions.
Add in a potential swell in COVID-19 infections this winter, and health officials are concerned about a convergence of the respiratory viruses — a “tripledemic” — that could tax health care systems this winter.
While flu and RSV, a common virus that can be serious in
infants and older adults, are not new, lack of recent exposure is likely contributing to their resurgence as more people socialize and ease protective measures, health experts said. Unclear is whether that will translate to heavier, or just earlier, seasons — and if their peaks might overlap with a COVID upswing.
“We’re hoping that at worst it would be something like a serious flu season,” said Dr. Erica Pan, the California state epidemiologist. “But it’s hard to know for sure.”
The Bay Area is seeing early surges in flu and RSV, although at this point not to the same extent as some other areas of the country. On Oct. 31, Orange County declared a local health emergency, citing “record numbers” of pediatric hospitalizations and emergency room visits due to virus infections.
As of Friday, 17 states were reporting high or very high levels of flu-like illness activity, according to the Centers for Disease Control and Prevention, with the number of U.S. cases and hospitalizations to date this season nearly doubling in the past week.
Nationwide hospitalization rates for flu last week were the highest for this time of year in more than a decade, per the CDC, while 9% of tests for flu were coming back positive.
For RSV, hospitalization rates were nearing mid-December peaks of previous years, according to another CDC report. And about 19% of PCR tests for RSV were positive, a higher rate even than during the summer of 2021, when a surge of the virus followed easing of COVID restrictions.
“We suspect that many children are being exposed to some respiratory viruses now for the first time, having avoided these viruses during the height of the pandemic,” said Dr. José Romero, director of the CDC’s National Center for Immunization and Respiratory Diseases, on a media call Friday.
Bay Area pediatric hospitals are seeing an effect. The UCSF Benioff Children’s Hospitals have seen “a significant rise” in respiratory illness cases, said Dr. Steven Bin, professor of emergency medicine there.
“For this time of year, this is definitely unique,” Bin said.
One factor is that RSV is affecting older children than usual, Bin said. Most children will get RSV before age 3, and for most it resembles a mild cold. But it can also cause serious illness, particularly in infants and elderly adults.
“There may be a component where these viruses, because kids have not been exposed to them, are causing more significant symptoms,” Bin said.
Dr. Alan Schroeder, associate chief for research of pediatric hospital medicine at Stanford Medicine Children’s Health, said the uptick in cases in the system resembles “a very busy winter month.”
About half those cases are RSV, with flu and COVID together making up about 10% and other winter pathogens such as rhinovirus the rest, Schroeder said. The hospital has “mostly been able to handle this surge” while navigating staffing issues widely seen across the U.S. health care system, he said.
“It may be that because we’re seeing so much RSV now, we don’t see quite as severe a winter,” said Schroeder. “On the other hand, it may be that this continues and we get even busier.”
In California, the state Department of Health reported upticks in the positive test rates for RSV (16.8%) and flu (7.9%) in the week ending Oct. 29, with flu activity highest in the southern region that includes Orange and San Diego counties.
Flu activity in the Bay Area region was categorized as low, meaning a positive test rate between 2% and 10%, according to the state Department of Public Health.
Dr. Susan Philip, the San Francisco health officer, said the county had yet to see “large increases” in flu rates this week. In Santa Clara County, health officer Dr. Sara Cody told supervisors Tuesday that emergency room visits for flulike illness were “a little above where we normally are for this time” but “not very high just yet.”
“It’s something that we’re watching closely,” Philip said. “We haven’t seen a concerning increase yet. But we know that it may be soon to come, because the fall and winter is when these viruses circulate.”
In Marin County, health officer Dr. Matt Willis said there are “clear signs of a surge in RSV” but that flu rates are “relatively low” and COVID case rates are “relatively stable.”
“Obviously, the concern is that if we see more cases of either COVID-19 or influenza, I think we’re more likely to see a surge of respiratory illness into our hospitals,” Willis said.
All of California’s counties were reporting “low” community levels of COVID-19 to the CDC as of Friday, reflecting a steady decline in case and hospitalization rates since late August. State epidemiologist Pan said that means the state is approaching this winter with less of its health care capacity already dedicated to COVID, as newer variants such as BQ.1, BQ.1.1 and XBB are starting to circulate more.
In another potentially good sign, CDC officials said Friday that while RSV activity is rising nationally, the rate of positive tests may be waning in some states in the Southeast and Mountain West areas, even as flu is increasing there.
Health officials and experts urge people to get the COVID-19 booster and a flu shot to bolster their immune defenses. As of Friday, 13.3% of eligible Californians age 5 and older had received the bivalent booster, according to state data, against a national level of 8.4%, per the CDC. For the annual flu shot, uptake among adults 18 and older is lower compared with this time last year, CDC officials said Friday.
Dr. Darvin Smith Scott, an infectious diseases specialist and clinical vaccine lead for Kaiser Permanente Northern California, said one reason may be that “people are worried to take them together.
“But it’s known to be safe and recommended to get them together,” Scott said. “The immunity will be protective as soon as possible.”
There is no current vaccine for RSV, though hopes that one might be close were piqued this week when Pfizer shared promising results from a trial of a vaccine given to pregnant women to protect their newborns. For now, mitigation measures against RSV and other respiratory viruses include handwashing, staying home when sick and considering masking in crowded, indoor settings, health officials said.
“Obviously, the concern is that if we see more cases of either COVID-19 or influenza, I think we’re more likely to see a surge of respiratory illness into our hospitals.”
Dr. Matt Willis, Marin County health officer