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Flu is on the rise in N.H.

  • Indications from outpatient surveillance (the blue line) and Emergency Department data (red line) throughout New Hampshire indicate that flu levels are similar to outbreaks in recent years. Courtesy—NH DHHS



Monitor staff
Wednesday, January 17, 2018

Flu season is ramping up in New Hampshire, just as it is in most of the country, with a particularly severe strain adding to the number of hospitalizations and even fatalities.

As of the end of 2017, five deaths in New Hampshire have been attributed to flu, which is on par with other seasons in which the dominant flu strain is a type known as H3N2, said Dr. Benjamin Chan, the state’s epidemiologist, on Tuesday.

“I think the overall message is that the flu season that we’re seeing in New Hampshire is on par with what we have seen in prior seasons ... when a H3N2 strain predominates. ... These tend to be more severe; hospitalization rates are higher; there are more deaths,” Chan said.

H3N2 refers to the type of proteins on the surface of the flu virus.

Flu is widespread in all states as of the first week of January, and its severity, going by a measure called ILI, for influenza-like illness, is much worse in most of the country than in northern New England, according to the Centers for Disease Control and Prevention.

Because the flu is not a reportable disease in most states, including New Hampshire, the number of cases is estimated through other measures. New Hampshire uses ILI, in which 19 health care providers report data about patients with flu-like symptoms but who haven’t been completely diagnosed as having the virus, as well as Automated Hospital Emergency Department Data, in which 19 state hospitals send in data about emergency room patients with acute respiratory illness.

Both of these peak in the first few months of most years and have been rising this year since early December. So far, however, their numbers remain lower than in recent years, particularly 2015. The report for the first week of January should arrive Wednesday of Thursday.

The flu vaccine is still available and, because the flu season usually lasts until at least March and often beyond, Chan said it is still useful to get vaccinated. That is particularly true for those who are most affected by the disease: the very young, very old or those with respiratory and other chronic ailments.

Flu vaccines are free for people under age 18 in New Hampshire and are covered by most health insurance plans for adults.

Different strains of the flu circulate around the world each year, and because it takes many months to produce vaccines there is something of a guessing game each year about which strains the vaccine should focus on.

Chan said this year’s vaccine does emphasize H3N2, as well as the B virus, which tends to circulate later in the season.

The vaccine is estimated to be about 35 percent effective for H3N2, a reflection of the severity of this strain. Despite that seemingly poor result, Chan said, the vaccine can reduce the severity or length of illness even if it doesn’t completely prevent it.

The portions of the vaccine that attack the B virus and another strain, H1N1, have higher success rates of 50 to 60 percent, Chan said.

“There are still weeks and weeks of flu season left; it’s not too late for people to get a vaccine,” he said.

(David Brooks can be reached at 369-3313 or dbrooks@cmonitor.com or on Twitter @GraniteGeek.)