It’s that time of year when families and friends come together to share holiday cheer and some spreading pathogens.
Peter Chin-Hong, an infectious disease specialist at the University of California, San Francisco, said people should be on the lookout for the “big four”: three respiratory viruses currently moving through the United States — influenza, COVID-19, and RSV — and one stomach virus — norovirus. .
According to WastewaterScan — an infectious disease surveillance network led by researchers at Stanford and Emory universities, with lab testing partner Verily, Alphabet Inc.’s life sciences organization. – These four viruses are spreading throughout the country.
In the case of the coronavirus, half of the U.S. east of Montana, Wyoming, Colorado and New Mexico is trending “up,” while western states remain generally low, with some hotspots in major cities like San Francisco. Seattle, Salt Lake City, and Boise, According to WastewaterScan.
But that’s likely to change as holiday travel transmits those viruses in what Chen Hong referred to as “the great vacation equalizer.”
He added that influenza is the one that attracts the attention of most doctors and researchers at the present time.
While federal The Centers for Disease Control and Prevention’s expectations for the severity of the flu’s impact this season were low. Chen Hong said he saw ominous signs coming from the two model countries of the United States: the United Kingdom and South America.
in the united kingdom, There were nearly four times as many cases of influenza earlier in December than at the same time last year. A similar trend occurred during the winter in South American countries such as Chile, Ecuador and Uruguay. Hospitalizations were higher than in the 2023 flu season. Elsewhere in Antarctica, seasonal flu rates were fairly typical.
Chen Hong suspects that the Centers for Disease Control and Prevention’s projections are based on the assumption that people have some “carryover immunity” from last year, and he said vaccines are helping.
But until the flu season reaches its peak, it’s difficult to know exactly what it will look like and whether vaccines have fully covered the circulating strains.
Chen Hong said there are two dominant strains of the virus circulating: H1N1 and H3N2, with the latter virus associated with more serious illness, which may cause an increase in hospitalizations abroad. But he said this year’s vaccine should cover it.
“It’s not too late” to get vaccinated, he said, noting that the flu season in the United States has just begun.
In addition, with the ominous threat of H5N1 avian influenza simmering in the background, there are concerns that it could be mixed up with human seasonal influenza. He said that getting vaccinated and avoiding seasonal flu will reduce the chances of such an occurrence.
Researchers and health officials say there is no evidence that the H5N1 virus can be transmitted between people. But to stay extra safe as the virus spreads through the country’s dairy herds and commercial poultry operations, people should avoid raw milk, raw eggs and undercooked meat. Pasteurization and proper cooking techniques inactivate the virus.
But it is not only the flu that threatens to thwart the nation’s good news.
Coronavirus (COVID-19), respiratory syncytial virus (RSV), and norovirus are also spreading.
COVID-19 recently began showing up at high levels in municipal wastewater, but Chen Hong said that doesn’t necessarily mean we’ll see an increase in hospitalizations. actually, While the number of coronavirus cases is on the rise, The CDC expects there There will be fewer cases in the United States this year compared to 2023.
“Some people think the reason people haven’t gotten it as much this year is because we got it more recently, especially in California, so the interim immunity kind of protects us, at least for now.” He said. “The other hypothesis is that we’ve had enough cycles of it in the population, so maybe it’s kind of low this year.”
But he said Covid had proven to be a smart and adaptable virus, constantly producing recombinant variants, so “coupled with low vaccination rates, that’s always the fear with Covid, that it will come back again.”
He said the best things one can do to avoid the three respiratory viruses — influenza, COVID and RSV — are to follow “the three D’s: vaccinate, ventilate and wash your hands often.” If you have to be indoors or in close proximity to others, masks make a difference. But try to socialize and walk around outdoors or in well-ventilated areas.
As for norovirus, which causes gastrointestinal upset and is typically spread through items handled by multiple people — such as airplane trays, handrails and buffet serving spoons — washing your hands is key. Additionally, keeping your hands away from your face is crucial; This is the primary route of infection.
Norovirus seems to be everywhere these days, Chen Hong said.
“Anecdotally, a lot of my colleagues came out with this,” he said.
In addition, there are some common rhinoviruses (the common cold), whooping cough, and pneumonia.
Of course, he said, if you’re not feeling well, stay home. Nothing stops a virus or infectious bacteria in its tracks like staying in isolation — even if it means missing out on holiday festivities.