It’s official: This year’s flu season is a record breaker.

There have been 21 weeks of elevated flu activity reported in the United States during the 2018-19 flu season, based on data from the weekly flu report released Friday by the Centers for Disease Control and Prevention.

That’s one week longer than the previous 10-year high, which occurred in the 2014-15 season and lasted 20 weeks, according to CDC spokeswoman Kristen Nordlund.

“This season has been record-breaking in terms of duration,” she said. The latest weekly report includes flu activity through the week ending April 13.

Typically, flu season begins in the fall and ends in the spring.

Flu activity is in decline; 11 states reported widespread influenza activity, compared with 20 states the previous week.

In terms of severity, the season is being described as moderate by the CDC, based on rates of reports of illness and hospitalization.

This was preceded by one of the most severe flu seasons in recent decades during 2017-18. That year, there were estimated to be more than 80,000 flu-related deaths and more than 900,000 hospitalization.

At least 36 million cases of influenza have been reported this season. As many as 57,300 people are estimated to have died from flu-related illness. That includes 91 children, the CDC said. Five of those pediatric deaths were reported in the latest update.

In addition, as many as 610,000 people have been hospitalized with flu, according to the report. The overall hospitalization rate for the week ending April 13 is about 62 people out of every 100,000. People 65 and older had the highest rate, about 206 people for every 100,000, followed by the 50-to-64 age group (about 78 for 100,000) and children under 4 years old (71 per 100,000).

And among the people who visited doctors or clinics, 2.4% reported flu symptoms during the week ended April 13; this is a decrease from 2.8% the prior week.

Nationally, the H1N1 flu strain has dominated overall, though H3N2 took the lead throughout the nation since late February. Last year, the H3N2 strain, which is known to cause more severe illness, dominated, leading to high rates of hospitalization and deaths.

The most important response to seasonal flu is for everyone 6 months or older to get vaccinated against the flu, according to the CDC. As long as flu is circulating in the area where you live, it is not too late to get vaccinated.

Prompt treatment with prescription antiviral drugs, such as Tamiflu and other medicines, is also recommended for anyone who is at high risk of developing complications, such as pneumonia, bronchitis, sinus infections and ear infections. Those at high risk include pregnant women, the old and the young — people 65 and older and children under 5 — and people whose immune systems are weak, such as cancer patients and sufferers of chronic diseases.

People over 65, children under 2 and individuals with medical conditions should also get a pneumococcal vaccination to prevent pneumonia, the CDC recommends.