Influenza is widespread statewide and hospitalizations are up 16 percent over the previous seven days as the respiratory illness kicks into peak season with a flurry of flu viruses, including a strain that zeros in on unvaccinated children.
While last year’s flu season was marked by an explosive number of deaths — nearly 80,000 nationwide and a declaration of a state of emergency in New York by Gov. Andrew M. Cuomo — the spate of illnesses tabulated in recent weeks statewide seems paltry by comparison, though not insignificant.
For the seven days ending Jan. 31, 988 people were hospitalized in New York, and 6,816 flu cases were laboratory confirmed during the same period, a 30 percent jump over the previous seven days.
The season is being driven by A strains of influenza — H1N1 and H3N2 — both of which are in circulation statewide and being passed in countless chains of coughing, sneezing, touching contaminated objects, and even holding conversations at close range with someone who’s infected.
H3N2 drove last year’s flu season, but it is barely a statistical blip this year. Most cases being recorded this year are caused by H1N1, data from the State Department of Health and the Centers for Disease Control and Prevention show.
In Manhasset, Dr. Bruce Farber, chief of infectious diseases at North Shore University Hospital, has found that H1N1 is the strain being seen disproportionately at his hospital compared with H3N2. Last year, the flu scenario was flipped at North Shore as it was at hospitals across the country: more H3N2, less H1N1.
“We’re seeing quite a bit more H1N1, which as a general rule tends to infect younger people,” Farber said Friday, referring to children and teens.
“H3N2, by comparison, tends to infect the classic older person with underlying medical problems: heart failure, chronic obstructive pulmonary disease, renal failure, dementia,” Farber said.
Last year’s H3N2, however, killed more than 200 children nationwide and tens of thousands of adults.
Northwell Health has an influenza tracking center, a space filled with computers and electronic maps, allowing flu hunters to trace areas of high influenza activity within the health care system’s service area. This electronic “nerve center” also allows the health care giant to most efficiently allocate masks, antiviral medications, intravenous bags and other flu-fighting resources throughout its system.
Farber said at his hospital alone there have been 100 cases of influenza caused by H1N1 from November through Jan. 31, compared with only 14 cases of flu caused by H3N2 during the same period.
Dr. Robert Amler, dean of New York Medical College’s School of Health Sciences in Westchester, said the science behind why a strain can prove deadly in one season but become mild in the next is not fully understood.
“It’s impossible to get into the mind of the flu virus,” said Amler, a former chief medical officer at the CDC. “There’s an ecological shift that occurs. These strains are out there, but at various times, one strain will become dominant over the other.”
Amler also said that with a strain that had spread so widely, it’s likely there is more immunity to it in the broader population. That leaves an opening, he said, for an opportunistic H1N1 to zero in on vulnerable lungs.
On Friday, Amler emphasized the importance of frequent hand-washing as one of the best defenses against flu infection. Hand sanitizers are also effective, as is the practice of staying clear of someone who has the flu. He recommends at least a six-foot distance for conversations.
As temperatures have dropped during the polar vortex, Dr. Richard Webby, a world-famous flu scientist who has tracked bird flu strains in remote regions of China, is encouraging the unvaccinated to get a flu shot.
Flu infections are more common in cold, dry weather, studies have shown.
“Now is the time to get a flu shot. It’s not too late,” said Webby, an infectious diseases expert at St. Jude Children’s Research Hospital in Tennessee.