Maine’s flu season is so far tracking less severe than last year – with fewer cases that tested positive for the virus – but flu is notoriously unpredictable and is spreading rapidly throughout most of the nation. Flu is widespread in most New England states, including Massachusetts, according to federal and state health data.

Maine had 510 confirmed influenza cases through Jan. 5 – the latest figures available – down from 768 during the same time period in 2017-18. Flu season runs from October through May. Maine has had three flu deaths so far this season, the Maine Center for Disease Control and Prevention reported.

“If you haven’t had your flu shot yet, you should run, not walk, to go get your flu shot,” said Dr. Kolawole Bankole, director/administrator of Portland Public Health.

The 510 cases are also much higher than some recent years. For instance, in 2016-17, there were only 128 cases through the same time period and 41 in 2015-16. But in 2014-15, 974 Mainers reported a positive flu test.

Maine ended the 2017-18 flu season with 9,018 cases and 82 deaths, the Maine CDC reported, the worst flu season in at least five years. About 225,000 people had tested positive for the flu in 2017-18, the U.S. CDC said, but the actual number of cases is much higher because many are not tested and recover at home.

Symptoms include fever, chills, muscle aches, swollen lymph nodes, sore throat, headaches, fatigue and coughing. Aside from immunization, basic hygiene such as frequently washing hands, getting plenty of sleep and staying away from sick people helps prevent spread of the flu.

Dr. Siiri Bennett, state epidemiologist at the Maine CDC, said that flu season is unpredictable, and can peak at any time.

“Some years it peaks in February, sometimes it peaks in March or April,” Bennett said. “Certainly, it’s been off to a much slower start than last year.”

The predominant strain this year is influenza A H1N1, which Bankole said tends to have less severe symptoms than the predominant strain circulating last season, influenza A H3N2.

Bankole said federal health officials have been able to develop vaccines that do a better job of preventing H1N1. Bankole also said that after the 2009 outbreak of H1N1, people developed improved natural immunity to the virus, which means symptoms tend to be milder even for people who contract the flu.

Flu vaccines are the best way to prevent influenza, according to public health experts, but there’s always some guesswork in predicting the strain that will be most commonly circulating in the upcoming season. In order to get the vaccine on the market in time, scientists have to predict the strains months in advance.

Last year, the vaccine was about 40 percent effective, the U.S. CDC said, while it was 48 percent effective in 2016-17 and 59 percent effective in 2015-16. For those who get a flu shot and still contract influenza, symptoms tend to be milder and not last as long, research has shown.

Bennett said preliminary indications are that “vaccines are very well matched for the strain” this season. The U.S. CDC typically announces initial vaccine effectiveness for the season in February, after collecting data.

Bennett said the flu often starts in the South and heads northward during the winter months, and Maine was one of the last states in the nation last year to experience widespread flu. Massachusetts has had about 2,200 confirmed influenza cases through the first week of January this season, according to Massachusetts state data.

Maine and New Hampshire were the only New England states with lower levels of flu activity through the end of December, the latest federal comparison data available, while most of the South already had been hit hard by the flu.

Joe Lawlor can be contacted at 791-6376 or at:

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