New studies from US and Europe reveal that a flu shot could wear off if these were done months before flu season. It has been a yearly event to get shots but lately these were offered as early as July to August by shops and clinics simply to take advantage of sales. Experts are now worried that getting vaccinated early reduces the chance of fighting more virulent strains of the flu and could undermine the effectiveness of the vaccination program overall.

Huffington Post was one of the first to report about this study and said that scientists from the Centers for Disease Control and Prevention has revealed that vaccine effectiveness was reduced by more than half for some flu strains and had diminished entirely for another five to six months after the vaccine was administered.

Michael Osterholm director of the Center for Infectious Disease Research and Policy at the University of Minnesota said that there is evidence that early vaccination, which is an attempt for pharmacies to get a larger percentage of the flu vaccine, should be discouraged by physicians and health professionals.

Osterholm also said that until more data has been recovered, the best recourse is still to get the flu vaccine just before flu season. Some scientists however do not agree and said that it is too early to warn the public. On the other hand, the CDC advises to get the vaccine by end of October. Once a person is vaccinated, it takes about two weeks for the immune system to respond so timing is crucial to getting vaccinated.

Another problem is that there is no exact date for flu season. All that health officials know is that an epidemic will mostly occur between late November and late March. The epidemic usually rises and falls over a period of 13 weeks.

Meanwhile, How Stuff Works posted that the flu shot wearing off is less likely to happen. According to Dr. James Conway, associate professor of pediatrics at the University of Wisconsin School of Medicine and Public Health, the immunity that a person gains from the vaccine will last from October till the flu season ends come spring. A person may even be immune for a year.

Scientists and influenza researchers are not yet advocating for a change in the recommended times to get the shot. Even getting the vaccine too close to the flu season may be unwise. They only recommend not to get the shot too early.