The flu season is beginning to dwindle as many parts of the country are seeing a decline in the number of influenza cases.
January and February are considered ‘peak season’ for the flu, so as we head into March, we should see the numbers begin to decrease.
The CDC (Centers for Disease Control and Prevention) has updated their Weekly FluView for the week ending on March 1, 2014.
Researchers are also releasing data on this year’s flu vaccine effectiveness.
Pandemic Deaths vs. Low Infections: Flu Across the U.S.
The CDC has released the data for week 9 (February 23- March 1, 2014) and shows good news mixed with bad.
- Good Flu News: U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) tested 6,748 specimens during this week, and only 8.7% of them tested positive for the flu.
- Bad Flu News: Unfortunately, however, the deaths that the 122 Cities Mortality Reporting System reported due to pneumonia and influenza were above the pandemic threshold at 7.9 percent (epidemic threshold is at 7.4 percent). In addition, during this week, doctors reported four influenza-related pediatric deaths, which brings the 2013-2014 flu season’s number to 65 pediatric deaths.
How Many People Are Going to the Hospital for Flu?
The Influenza Hospitalization Surveillance Network (FluSurv-NET) conducts population-based surveillance for laboratory-confirmed influenza-related hospitalizations. According to this group, this flu season has sent 28.5 people out of every 100,000 in our population to the hospital. Many experts believe that this is actually a low estimate, since hospitals don’t always test for the flu, and in some cases the hospitalization is the result of complications that come after a flu infection. The data collected this year suggest that people ages 65 years and older are the most likely to be hospitalized due to the flu.
Influenza-like Illness: How Many People are Going to the Doctor?
The CDC also collects data on the number of people that visit an outpatient center (doctor’s office, or urgent-care) for influenza-like illnesses. The normal, or ‘baseline’ percentage for these visits is 2.0 percent, which also happens to be exactly the percentage for week 9. That means that less people are going to the doctor for influenza symptoms (fever over 100 degrees F, cough, and/or sore throat) than during the height of flu season.
Where is Flu Activity Highest?
Influenza activity maps show how geographically widespread influenza is, but does not measure the severity. Activity ranges from no activity to widespread. For week 9, the CDC notes that there is widespread influenza activity in only eight states; Connecticut, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, and Virginia.
States with regional activity include: Arizona, Arkansas, Illinois, Indiana, Missouri, Ohio, Oklahoma, Pennsylvania, South Carolina, Texas, Utah, and Vermont. There was local influenza activity in Alabama, Alaska, California, Delaware, Florida, Idaho, Iowa, Kansas, Kentucky, Louisiana, Michigan, Minnesota, Montana, Nebraska, Nevada, New Mexico, North Carolina, North Dakota, Oregon, Rhode Island, South Dakota, Tennessee, Washington, West Virginia, Wisconsin, and Wyoming. There was sporadic influenza activity in Colorado, Georgia, Hawaii, and Mississippi, and The U.S. Virgin Islands is the only place reporting no influenza activity.
Flu Vaccine Effectiveness
The seasonal influenza vaccine, or flu shot, is what the CDC considers to be the best way to protect yourself from the flu. Scientists study past flu seasons to gain perspective on what flu viruses might be circulating for the next season, and work to predict the strains for the following year. Vaccine manufactures begin to make the flu shot many months in advance of the flu season to keep up the supply.
There is no real way to know what flu strains will be circulating or which ones will be the most popular, so scientists have to make an educated guess.
When the scientists and experts predict the right strains, the flu shot can be very effective – if they pick the wrong strains, more people get sick from the flu, even if they get the flu shot.
As the flu season begins to wind down, we’ll be seeing more studies on how effective this flu season vaccine was.
- In a Canadian study, researchers found that the flu shot cut the risk of flu-related hospitalizations in Canada by 59 percent. While this is a preliminary estimate, researchers have also found that about two-thirds of severe flu illnesses in adults were those younger than 65 years of age.
- A law in Connecticut requiring children who were entering daycare or preschool to get the flu shot has reduced flu-related hospitalizations by 12 percent, according to a new study published in the CDC’s Morbidity and Mortality Weekly Report. New York City and New Jersey also have this law for children in daycares and preschools. Experts think that increasing the vaccination rate (84 percent in 2012-2013 from 68 percent in 2009-2010 reduced the number of flu-related hospitalizations in children ages one to four.
A Light at the End of the Tunnel
The flu season is starting to dwindle, and hopefully we will continue to see lower numbers as the winter turns to spring and we step out of the cold and flu season. Experts have to make their best predictions on what flu strains will be circulating for the next flu season early on so that vaccine manufactures can make enough vaccine.
If experts predict correctly, and the strains all match up, then the flu shot tends to be effective – let’s see how next year’s flu season shapes up.© Copyright 2014 Janelle Vaesa, MPH, All rights Reserved. Written For: Decoded Science