This flu season was the longest on record, officials say
The 2021-2022 flu season was the longest one on record in the U.S., officials said, but it was also one of the most mild. Credit: Kendall Rodriguez
The 2021-2022 flu season was the longest one on record in the United States, officials said, but it was also one of the most mild.
Influenza activity began to increase in November and remained elevated through mid-June, according to a report recently released from the Centers for Disease Control and Prevention.
In New York State, there were two peaks in lab-confirmed flu cases, one in December and the second in April.
The report notes that flu season usually peaks in February and drops off in the spring, with surveillance ending around May. This year, the Health Department said it would extend the flu surveillance period beyond May because of persistent elevated flu activity. Experts said it’s not clear if the unusual flu season pattern is somehow linked to the COVID-19 pandemic.
WHAT TO KNOW
- The 2021-2022 flu season was the longest one on record, stretching from about November 2021 to June 2022. But most of the cases caused mild illness.
- In New York State, there were two peaks in lab-confirmed flu cases, one in December and the second in April.
- Experts said they are not sure but suspect the unusually long season is likely related to the COVID-19 pandemic.
“Quite frankly, it’s a little odd,” said Dr. Bruce Farber, chief of public health and epidemiology for Northwell Health. “The flu season was expected to be long and difficult after the 2020-2021 flu season was so mild.”
There were 125,709 confirmed lab cases of influenza this past season in New York, according to the state Health Department. In 2020-2021 there were just 4,921. The previous pre-pandemic season of 2019-2021 had over 157,000 cases.
Nationally, the CDC estimates that this year’s influenza virus infection resulted in between 8 million and 13 million symptomatic illnesses, 3.7 million to 6.1 million medical visits, 82,000 to 170,000 hospitalizations, and 5,000 to 14,000 deaths in the U.S. The agency said those are lower than estimates for any of the 10 influenza seasons preceding the pandemic.
Farber pointed out that the flu virtually disappeared in 2020-2021 as a result of masking, social distancing and other safety precautions taken due to the pandemic.
While flu did not come back in a particularly virulent way, meaning the illnesses were relatively mild, it was prolonged.
Farber said doctors are also seeing more cases of respiratory illnesses, such as respiratory syncytial virus (RSV), which usually appear in the winter.
“It’s hard for me to think that there's not some relationship that we've not been smart enough to understand yet,” Farber said, about any correlation between the COVID-19 pandemic and the unusual flu season. “We do know that people who got COVID at least made some antibodies against other coronaviruses so certain common colds, those caused by coronavirus, not obviously COVID, were potentially less common in the setting of COVID epidemic, but that would not apply to flu and RSV.”
Farber also pointed out that some people make antibodies after a respiratory illness that could give them some level of immunity against other respiratory illnesses for a relatively short period of time.
“Whether that's playing into this sort of late onset flu or summer is not clear, but it could be another potential explanation,” he said.
In addition, fewer adults across the U.S. got the flu shots this year, CDC statistics show. About 34.7% of adults between the ages of 18-49 received their vaccination. It was about 50% for adults between the ages of 50 to 64 years and 67.7% for adults 65 years and older. About 55.3% of children under the age of 18 received flu shots as of April 2022.
Lisa joined Newsday as a staff writer in 2019. She previously worked at amNewYork, the New York Daily News and the Asbury Park Press covering politics, government and general assignment.
