Flu viruses got a jump on the season this year, circulating sooner than expected and causing outbreaks around the country in waves of infection that continue to intensify, state and federal flu scientists say.
On Long Island, the specter of an intensifying flu season is worrying public health officials who point to possible crowding and overcrowding in homes as friends and relatives continue to accommodate families displaced by the October superstorm.
Suffolk health commissioner Dr. James Tomarken said even in the face of less than optimal living conditions, flu vaccination can prevent infection. This year's flu vaccine, he added, is a solid match against circulating strains.
"We are very concerned that those residents who have already suffered a great deal as a result of Sandy will not have to suffer additionally from influenza, so we encourage them to get their flu immunization," Tomarken said.
Sandy a factor
Crowding creates the opportunity for increased viral transmission, explained Dr. Gary Leonardi, an influenza expert and virologist at Nassau University Medical Center, who monitors flu activity on Long Island for the state Health Department.
In addition, stress from the storm and its aftermath, Leonardi said, has the potential to make people even more vulnerable to the flu as well as other respiratory infections because stress weakens immunity.
"Anyone who is unvaccinated can catch the flu, period," Leonardi said. "But crowding is the recipe for spreading respiratory illness rapidly.
"If we all lived in our own little bubble, we wouldn't get sick with respiratory viruses," Leonardi continued. "But we also wouldn't build up our immune system because we would be shut off from all kinds of pathogens.
"The reality is that we are constantly exposed to pathogens, all day, everyday. So it helps when you can prevent illness because the flu can be pretty severe."
The annual concern about the flu is not baseless, experts say, even though influenza receives second billing in so-called cold and flu season. The flu kills about 36,000 people annually and is the underlying reason for more than 200,000 hospitalizations nationwide, according to the Centers for Disease Control and Prevention. Most flu deaths occur as a result of pneumonia.
Federal public health officials recommend the flu vaccine for healthy individuals age 6 months and older. The flu shot is not recommended for those who have an allergy to eggs, which are used in vaccine manufacturing.
Flu season usually runs from November through late March, but this year it got an earlier start with the first signs of viral activity appearing in September.
New York is one of eight states reporting widespread flu activity, say CDC flu scientists who track influenza-related hospitalizations nationwide.
Leonardi noted most of New York's flu activity has been concentrated upstate, but he underscored that flu viruses know no borders and that exposure may be as close as one's next handshake or the sneeze from a passerby.
"We know that all respiratory viruses spread easily when aerosolized," said Leonardi referring to sneezing or coughing, which force viral particles into the air.
"And they stay in the air a good period of time," Leonardi noted.
Studies have shown that a single cough or sneeze can propel viruses by as much as 15 feet. The extraordinarily hardy pathogens are capable of remaining viable for more than an hour while suspended at ceiling height before drifting down to contaminate surfaces.
Leonardi, who publishes an NUMC newsletter on respiratory viruses of all types, said the influenza subtype causing outbreaks and notable cases of infection this year is the seasonal variant dubbed A/Victoria H3N2.
The names of flu viruses recognize the site where the pathogen, which becomes part of a long lineage, was first isolated. The H3 and N2, refer to proteins on the viral surface.
Federal flu trackers have voiced concern about A/Victoria because of the way it has already swept through parts of the South and Southwest.
Aside from the 2009 H1N1 globe-circling pandemic strain, which began in spring, this year's start is the earliest for seasonal flu since the 2003-04 influenza season when a fast-moving strain, A/Fujian, another H3N2 subtype, also started in September.
A national panic ensued that season when 153 children died of the flu, recalled CDC scientists during a news briefing last week.
This year, flu scientists mounted a detailed tracking effort of flu viruses on the move, hoping to get ahead of the curve by recommending vaccination.
Nationwide, pediatric mortality has come nowhere near the death toll of that long ago flu season -- five children have died so far, none on Long Island.
Much of the the CDC's flu data is reported retrospectively, experts say, with the majority of the incidence estimates coming from state health departments. Figures involving hospitalizations and mortality are from selected medical centers around the country. Sometimes it takes weeks for the information to reach the CDC's central database.
Flu scientists at Columbia University say the timing and severity of seasonal influenza outbreaks may one day be better predicted using a sophisticated web-linked tool designed by scientists there and based on techniques used to forecast weather patterns.
Reported last week in the Proceedings of the National Academy of Sciences, the preliminary method, said Dr. Jeffrey Sharman, an assistant professor of environmental sciences and one of the developers, said the real-time technique could eventually help inform decisions on how many vaccines and antiviral drugs to stockpile. In the event of a severe outbreak, he said, it would aid decisions on other measures, such as closing schools.
IS THIS YEAR'S VIRUS A GOOD MATCH?
Every year, flu viruses are selected for inclusion in the seasonal vaccines based on the predominant strains in circulation.
Two A strains of flu and one B strain are normally selected. Only proteins from viruses are used in vaccines. They are deactivated and incapable of transmitting infection. Here is this year's formulation:
A/California/2009 (H1N1)-like virus
A/Victoria/2011 (H3N2)-like virus