Flu Season Vaccine

FILE PHOTO / THE MORNING CALL

Flu vaccine is a good match - It's probably not a coincidence:

The flu vaccine is a good match to the strains of the virus now circulating, and the flu season thus far has been relatively mild nationally.

The overall effectiveness of the vaccine is 59 percent, the Centers for Disease Control and Prevention announced Wednesday.

"This means that getting a flu vaccine this season reduced the risk of having to go to the doctor because of flu by nearly 60 percent," said Dr. Joseph Bresee, chief of the CDC's Epidemiology and Prevention Branch. "It's good news and underscores the importance and the benefit of both annual and ongoing vaccination efforts this season."

Specifically, the vaccine is 51 percent effective against the H1N1 strain responsible for most flu illness this season, 76 percent effective against all influenza B strains and 79 percent effective against the B/Yamagata lineage of B viruses, according to the CDC.

That's a big improvement over last winter, when the vaccine provided a mere 18 percent effectiveness against the then-dominant strain, which proved to be particularly virulent.

By January 2015, 8,000 Pennsylvanians a week were testing positive for the influenza. And by the time the 2014-15 flu season was over, the state Health Department had recorded more than 55,000 confirmed cases across the state — including 221 deaths, mostly of people older than 65.

Despite the good news about this season's vaccine, flu remains a major threat and vaccination is widely considered the best defense.

According to the CDC, flu activity has been elevated for five consecutive weeks. The past 13 flu seasons have averaged 13 weeks in length, with a low of one week to a high of 20 weeks.

"Flu activity this season started a bit later and has been lower so far than we've seen during the previous three seasons, but activity is still on the upswing and expected to continue for several weeks," Bresee said. "Flu causes serious illnesses and deaths every year. This season, CDC has received reports of hospitalizations and deaths in young, otherwise healthy people who were infected with influenza A H1N1, but not vaccinated."

In Pennsylvania, the number of flu cases reported weekly surged by more than 50 percent — to about 900 — in the week ending Feb. 20, compared with the week before, according to the state Department of Health.

The Lehigh Valley remains ground zero for flu activity in the state, with Lehigh and Northampton counties reporting far more influenza cases than anywhere else.

Across the state, 3,125 confirmed cases of the flu, including seven deaths, were reported from Oct. 3 to Feb 20, according to the state Department of Health. Of those, 832 — or more than one-fourth — were in Lehigh and Northampton counties.

Adults infected with the flu are typically contagious for up to five days. Children, who may also experience vomiting, can be contagious for more than a week.

Influenza is estimated to result in 150,000 hospital admissions and 24,000 deaths a year in the United States.