Brace yourselves: a key flu strain may be more aggressive this year, and experts say the vaccine could be dramatically less effective than in the past.
Already, more than half of New York’s counties — including Nassau and Suffolk — have had cases of the infection confirmed by Wadsworth Center, the state Department of Health’s laboratory in Albany. Statewide, the number of people hospitalized for the flu jumped 56 percent compared with recent weeks, according to the state’s Weekly Surveillance Report, last updated on Nov. 25.
Nationally, more than 7,000 cases of the seasonal illness have been confirmed by the U.S. Centers for Disease Control and Prevention, double what was seen a year ago, experts said Wednesday.
The strain of flu causing the most illness in New York — influenza A H3N2 — is the same one that caused illnesses in a deadly wave south of the equator this year.
Influenza season unfolds below the equator between July and October and often is a bellwether of what awaits the Northern Hemisphere. It’s not clear whether the same fate awaits the Northern Hemisphere, local and national experts said Wednesday.
Early estimates suggest this year’s flu vaccine may have had only 10 percent effectiveness in Australia, which experienced a record-high number of flu cases and deaths this year, a team led by Drs. Catherine Paules and Anthony Fauci of the National Institute of Allergy and Infectious Diseases reported in last week’s New England Journal of Medicine. The vaccine has the same formulation as the one in the United States.
Although the flu vaccine is usually 40 percent to 60 percent effective, local doctors said the Australian example should not dissuade people from being vaccinated in this country.
“A low level of [vaccine] efficacy means more individuals may be affected by the flu,” said Dr. Bruce Hirsch, a specialist in infectious diseases at North Shore University Hospital in Manhasset, a division of the Northwell Health system. But “a modest benefit [from the vaccine] is better than no benefit, especially with an illness that can cause between 12,000 and 56,000 deaths in a year.”
A flu shot helps moderate the infection’s severity, especially for those most likely to develop complications.
“The virus can invade the lungs, leading to a severe viral pneumonia in some people,” said Dr. Alan Bulbin, director of infectious diseases at St. Francis Hospital in Roslyn, adding that it can compromise the respiratory tract with shortness of breath and lower oxygen levels.
People at greatest risk of complications include the elderly and people with immune-compromising conditions, including heart conditions, respiratory disease, chronic infections, cancer and diabetes, doctors said. According to Bulbin, body weight may be another compromising factor.
“A young healthy person with the flu may not feel anything significant,” Hirsch said. “But when a person who is dealing with heart failure, diabetes or chronic obstructive pulmonary disease, they don’t have the same kind of reserve capacity to remain well.”
Dr. Aaron Glatt, chairman of the department of medicine at South Nassau Communities Hospital in Oceanside, said he was surprised that some people on Long Island and elsewhere in the greater metropolitan area do not recognize the flu as a serious illness.
His hospital commissioned a poll earlier this year that revealed about a third of people surveyed acknowledged going to work sick.
“If someone doesn’t want to take high blood pressure medicine, that’s a personal health decision that affects no one else,” Glatt said. “But not getting vaccinated not only affects the individual, but other people as well. That’s no longer a personal health decision, it’s a public health decision.”