Figure 1From: Difference in immune response in vaccinated and unvaccinated Swedish individuals after the 2009 influenza pandemic Overview of the ILI study participants. 1,971 study participants entered the study in the winter of 2009 (time point A); 67 samples were collected from study participants and household members during home visits triggered by an H1N1+ or coronavirus + PCR (detected in nasal swabs sent at time point B); 918 study participants returned for the follow-up sampling in the spring of 2010 (time point C).Back to article page