Side effects commonly reported include swelling, redness, or pain at the injection site, which usually resolve soon after vaccination. Fever, headache, fatigue, muscle aches, and a variety of allergic reactions, occurring shortly after vaccine administration, have also been reported less frequently.
There have been fewer than ten cases of Guillain-Barre syndrome reported in H1N1 vaccine recipients. These numbers are consistent with normal background rates of the illness. All the individuals have recovered.
Some deaths have been reported in people who have been vaccinated. These are all investigated by WHO, and so far in no case is there a direct link to H1N1 vaccine as the cause of death.
There have been no differences in the safety profile of inactivated vaccines with or without adjuvant, and infectious attenuated vaccines..
Although intense monitoring of vaccine safety continues, all data compiled to date indicate that pandemic vaccines match the excellent safety profile of seasonal influenza vaccines, which have been used for more than 60 years.