Maine just suffered through its worst influenza season in at least five years, with 9,018 reported cases in 2017-18, a 55 percent increase from last season.
The flu season runs from October through late May, and the Maine Center for Disease Control & Prevention wrapped up its annual flu season weekly reports last week. The agency counted 1,750 hospitalizations to go with the 9,018 reported cases, which surpassed the 5,830 cases in 2016-17. Eighty-two people died in Maine from the flu, according to the Maine CDC, compared with 71 the previous season.
Dr. Siiri Bennett, state epidemiologist at the Maine CDC, said it’s difficult to compare flu seasons because different strains of the virus circulate, and because Maine’s reporting of cases improves every year. Bennett said some of this season’s increase can be attributed to better reporting by doctor’s offices and health organizations to the Maine CDC, although there’s no doubt that 2017-18 was a severe season.
“It was certainly a very vigorous flu season,” Bennett said.
Dr. Kolawole Bankole, director of the Portland Public Health Division, said the flu was “big time” this season.
Flu cases accelerated in December and peaked in February before dropping off in mid-March and April, followed by a steep decline in May.
Flu is much more common than what is publicly reported because the data represents positive lab tests for influenza. Many thousands more contract the flu but recover at home and are not tested.
MORE SERIOUS STRAIN DOMINATED SEASON
The federal Centers for Disease Control and Prevention also reported that this year’s flu season was severe nationwide, with widespread activity in all states except Hawaii.
The early to middle periods of this year’s flu season were dominated by the H3N2 influenza A virus, a more virulent strain that typically results in higher rates of hospitalization. In January, about 25 percent of cases required patients to be hospitalized. But the second half of the season saw the emergence of influenza B and other flu strains that usually cause less severe illness, and by the end of the season the hospitalization rate declined to 19 percent of all cases. Sixty percent to 70 percent of all flu cases in Maine were H3N2 influenza A.
Bennett said it’s not uncommon for the predominant strain to change midway through the flu season. “I’m not sure why, but there is frequently a shift partway through the season,” she said.
Nationally, the federal CDC reported 223,487 positive tests for the flu, with about two-thirds of the cases influenza A.
Also this season, the flu vaccine was 36 percent effective, according to the federal CDC, down from the previous two years. The vaccine was 48 percent effective in 2016-17 and 59 percent effective in 2015-16.
Bennett said the CDC “strongly recommends” vaccination even in years when the vaccine is not as effective. The vaccine is never 100 percent effective because in order to get the vaccine to the market in time for flu season, scientists must predict months beforehand which strains of the flu will be the most common variant circulating.
“Even if a vaccine were only 25 percent effective, it would prevent many hospitalizations,” Bennett said. “If you can prevent a certain number of hospitalizations and deaths, it’s well worth it.”
For those who get a flu shot and still contract influenza, symptoms tend to be milder and not last as long, research has shown.
MAKING PREPARATIONS FOR NEXT SEASON
The National Institutes of Health reported in April that scientists are working on a new flu vaccine that would provide “broad protection against various influenza virus strains,” which would greatly improve vaccine effectiveness.
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.
Meanwhile, of the 141 outbreaks reported at institutions – an outbreak is defined as three or more cases in one location – 116 were at long-term care facilities, such as nursing homes.
“That’s the population most at risk, because often people are immune-compromised, and as people get older the body just doesn’t respond as efficiently to infections,” Bennett said.
The average age of a patient hospitalized for the flu this season was 60, the Maine CDC said.
Bankole said Portland recognized the severity of the flu season this year and started a partnership with the Visiting Nurse Association to operate immunization clinics, including one at City Hall.
Those efforts will be improved and expanded for next flu season, Bankole said. He said the city also will work more with hospitals and the city’s homeless shelter to improve policies surrounding when people who are homeless become hospitalized with the flu.
Bankole said that when a patient is homeless and discharged from the hospital after testing positive for the flu, Portland Public Health wants to make sure quarantine procedures at the homeless shelter are followed when needed, because often patients are still contagious when returning to a congregate living area.
Joe Lawlor can be contacted at 791-6376 or at:
jlawlor@pressherald.com
Twitter: joelawlorph
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