For many years, the elderly have been told that a simple flu shot could keep them safe against pneumonia. It seems the benefic result in their case has been overrated, according to a study published in the August issue of the journal The Lancet.

More exactly, some seniors getting the flu shot might not be much protected against the virus compared to those who choose to not have it at all, Michael Jackson, lead author of the study and former postdoctoral fellow at Seattle’s Group Health Center for Health Studies said.

“Basically, its been taken for granted for a decade that this vaccine is effective in all seniors. We’re starting to find out maybe that’s not the case,” Dr. Jackson said.

More than 3 million develop pneumonia annually in the US and more than 60,000 Americans die from the disease - an inflammation of the lungs that’s usually caused by infection with bacteria, viruses, fungi or other organisms. At increased risk are older adults and people with chronic illnesses or weakened immune systems, but it can also strike young, healthy people. Worldwide it’s a leading cause of death in children. Pneumonia is the sixth leading cause of death in the US.

For the study, Dr. Jackson and his team analyzed 3,519 seniors between 65 and 94 over the course of three flu seasons to determine the efficiency of the vaccine. Some 1,173 of the people had pneumonia while the other 2,346 people did not have it. The researchers did not find strong evidence that the vaccine helped prevent against pneumonia. More exactly, the vaccinated seniors who caught the flu were as likely to develop pneumonia as unvaccinated seniors who caught the flu. Previous studies have suggested that the flu shot reduces the risk of pneumonia in seniors by 20 to 30 percent.

However, Dr. Jackson said the study should encourage seniors to not get vaccinated. Instead, he said there is room for more improvement of the flu shot in order to fit seniors who may not benefit from it such as higher doses or a different formulation.

“Despite our findings and even though immune responses are known to decline with age, I still want my grandmother to keep getting the flu vaccine. It is safe, so it is worth getting, even if it might lower the risk of pneumonia and death only slightly,” he said.

The vaccine is still worth having because it reduces the risk of getting the flu, which might have serious consequences in the elderly whose body has to fight with other conditions coming with the age as well.

“It should not deter people from getting the flu vaccine because influenza is an unpleasant illness in itself and the vaccine is particularly important for elderly people with chronic diseases who have a weakened immune system and are susceptible to developing pneumonia."