What's happening to the flu? Doctors explain impact of COVID-19 precautions in California

SAN FRANCISCO -- Amid a deepening pandemic, doctors are crediting masking, hand-washing and distancing with stopping one virulent disease in its tracks--the flu.

"The silver lining is we're not seeing the flu. The flu is almost absent," said Dr. Andra Blomkalns, Director of Emergency Medicine for Stanford Health.

"There's no question this year is an extraordinary year," said Kaiser Permanente flu expert Dr. Randy Bergen, who told ABC7 News that by early January, California would normally see a serious uptick in flu cases, but not this year.

"We are testing still thousands of people in our emergency room settings and in our hospitals for a combination of COVID and flu tests and we're essentially seeing no flu. Some weeks we'll have no cases, other we'll have maybe one or two cases."

Some say all the precautions taken to prevent the spread of COVID-19 are keeping flu cases at bay. But if they're so effective with one virus, why not the other?

"It's a great question," said Stanford global health professor Dr. Yvonne Maldonado, who explained part of the answer may lie in pre-coronavirus studies in recent years that revealed an odd sort of competition among viruses.

"It could be something about infection with one virus may somehow decrease the risk of infection with others," said Maldonado. "Now whether it's immunity or they just suppress the growth of another virus, it's not really clear, but there's certainly an inkling from a couple of years ago, that viruses can compete."

Another contributing factor -- many more people received flu vaccines this year.

And, many children are not in school, and not gathering with friends nearly as often as they would normally.

"Flu always starts in the schools. It starts with children," said Bergen.

Experts caution people not to let their guard down. There's still plenty of time this winter for the flu to make a comeback.