NY Travel Clinic

Effectiveness of the Flu Vaccine This Year

There is no question that acquiring influenza is not a pleasant experience. Most people develop symptoms of a runny nose, cough, general malaise and muscle aches. Countless people have to take time off from work and school. And in young children and elderly, the illness can be severe enough to require hospital admission. To make matters worse, thousands of people who acquire the flu congest the emergency rooms looking for a magical treatment.

One of the best ways to prevent influenza is to get vaccinated in late October, just before the flu season starts.

Every year since 2004, officials with the Centers for Disease Control and Prevention estimate the predominant strain of influenza based on what dominant strains are present in the southern hemisphere. They then use these estimates to advise vaccine manufactures on which strains may be present in the upcoming winter season. The manufacturers then make a vaccine based on these recommendations. Once the vaccine is administered to the public, throughout the season, researchers from CDC collect patient data and estimate the effectiveness of the seasonal influenza vaccine.

The CDC recommends an annual vaccine for all individuals six months and older. The CDC believes that the vaccine can help prevent the morbidity associated with this infection.

So how effective was the flu vaccine this past year?

First there is no vaccine that offers one hundred percent protection against the influenza virus. In the past decade, the effectiveness of the flu vaccine has ranged from 40-70 percent.

A recent report published by the CDC reveals that the current vaccine only was 48% effective. The researchers collected data from 3,144 children and adults who were enrolled in the US Influenza Vaccine Effectiveness Network to estimate the effectiveness of the vaccine. All the participants who got sick were then laboratory tested to confirm that they did indeed get the influenza virus infection.

This low rate of effectiveness of the vaccine is not surprising. It is very difficult to predict what strain of influenza virus may appear during the winter season. With only a 50% chance of success of effectiveness, one wonders if it is worth getting the flu shot. So far, the vaccine has not been associated with any morbidity and is relatively safe. If the pubic had to pay for the influenza vaccine, it is doubtful many would get vaccinated with such a low success rate. What is also more difficult is that no one can predict the effectiveness of the vaccine in one individual or the other.