The U.S. is in the midst of its first “high severity” flu season in seven years. The U.S. has also seen the highest rate of doctors visits for flu-like illnesses overall — which include influenza, Covid and respiratory syncytial virus (RSV) — in 15 years. While flu activity has slowed in recent weeks, experts warn that the season isn’t over yet. Although experts don’t know exactly why the flu seems so bad this year, they say several factors may be to blame.

As influenza cases and hospitalizations continue nationwide, some experts are labeling this year as one of the worst flu seasons in recent history. "This flu season has seen the highest number and severity of influenza cases in recent years, as reflected in the percentage of positive tests across our emergency department, urgent cares, and outpatient offices," said Dr. Henry Fraimow, an infectious disease specialist at Cooper University Health Care. As this season goes, there's not a solid answer as to why it's so bad. "There's theories, but nobody's really sure," Topiel said, explaining that data from this season still needs to be collected. Topiel shared a few different hypotheses, including a lack of built-up immunity from social distancing and masking in the last few years as a result of the pandemic.

Truth about why this year's winter flu season has been SO awful - and why next year's could be even worse. The US Centres for Disease Control and Prevention classified this flu season as ‘high severity’ for all age groups; doctors’ appointments for flu symptoms and hospitalisations have reached the highest levels in 15 years, since the 2009/2010 swine flu outbreak. He believes that isolating during lockdowns, and wearing masks in public and keeping a safe distance from each other, may have contributed to lowered immunity against flu bugs. The weather may also have caused flu rates to rise, as months of rain and freezing temperatures kept more of us indoors for long periods of time.

At Inova Health, flu cases last week doubled the number of cases from this time last year. About 21,000 lives have been lost, including 98 children. The circulating strain is following the national trend, which is influenza A. The majority of states are reporting high or very high flu levels.

CDC: 370,000 hospitalizations and 16,000 deaths across the country tied to influenza. In California alone, more than 900 people have died of the flu since October. Only around 45 percent of American adults have gotten their shot this winter. "It has been very bad, and I think this is the hard part, knowing what the virus is going to do," doctor says.