Like many others, you may be wondering whether to be vaccinated against influenza. You know that elderly people and those with compromised immune systems can suffer life-threatening complications from the flu—but you’re healthy, so shouldn’t you be able to weather it if you catch it?

According to the CDC, up to 20% of Americans get the flu each year. More than 200,000 people in the U.S. are hospitalized each year, and about 3,000 to 49,000 deaths are flu-related. But at the same time, there are numbers of scientists who insists that the risks of serious complications from the flu for healthy people are extremely low, likely around the same as the risk of having an adverse reaction to the vaccine itself and these risks are real and accepted by the medical community.

1. Some studies indicate that when the match between the vaccine and the circulating viruses is good, there are 70-90 percent fewer cases of the flu among healthy vaccinated adults under 65. Even when there is a mismatch, there were 50 percent fewer cases of the flu in those who were vaccinated. Young adults who get the flu shot take fewer days off work, visit the doctor less often, and take fewer antibiotics and over-the-counter medications. They are also less likely to end up in hospital.

2. Thimerosal is a mercury-based preservative that has been used since the 1930s in a variety of medications and cosmetics. It is used to prevent bacterial infections, which can be an issue in multi-dose vaccines. Because mercury is a known neurotoxin, controversy has swirled around this additive, raising suspicions that it might be linked to autism. However, studies that have looked at thimerosal in routine childhood immunizations could not establish a link. The form of mercury in thimerosal, ethylmercury, is flushed quickly from the body (unlike its cousin, methylmercury, which accumulates and causes neurological damage). Nevertheless, the pharmaceutical industry is working on removing thimerosal, to increase patients’ confidence. It has already been removed from most vaccines—however, hepatitis B vaccines and most flu vaccines still contain it.

3. Some other studies found virtually no evidence to support flu shots as a public policy reduced flu transmission rates. What the researchers found was the vast majority of studies drug companies used to demonstrate the effectiveness of vaccines were so flawed that drawing conclusions from them was impossible or problematic. The studies often had no control groups, had a health bias (used really healthy lifestyle people) and methodologies were not well explained etc. Compounding this is the fact that almost no medical follow-up exists for people who get the vaccines.

4. Flu shots and the nasal flu vaccine work by causing antibodies to develop in the body. These antibodies provide protection against infection from the flu virus. This antibody reaction may cause fatigue and muscle aches in some people. Sometimes people who get vaccinated during flu season catch the flu in the two weeks before the vaccine has a chance to work. While it’s human nature to see a link between the two events, there’s no medical evidence that flu vaccines cause flu or make people susceptible to flu.

5. Each year, the flu vaccine contains several different kinds of the virus. The strains chosen are the ones that researchers say are most likely to show up that year. Recently, however, some influenza strains have developed resistance to an antiviral called amantadine, so NACI no longer recommends its use. Last winter, some flu strains, mainly in Europe, developed resistance to another anti-viral drug, oseltamivir (Tamiflu). So far, it is still considered effective against strains circulating in other countries.

6. Some people who gent the flu shots, may experience some side-effects, for example soreness and/or swelling in arm after getting a flu shot. Some people have cold-like symptoms, including sniffles, headache, runny nose, sore throat, cough, and body aches for a day or two after getting the flu shot. In some cases, patients may also experience a low-grade fever. Sometime serious side effects from the flu vaccine may occur.