HealthNews.in

The influenza pandemic in 2009 led to the vaccination of high-risk groups with new vaccines targeting swine flu, when only limited information about the safety of the vaccines was available.

Researchers at UCL and vaccine manufacturers GSK found that Pandemrix had an acceptable safety profile in all age and risk groups studied.

The researchers analysed side effects reported within 6 months in more than 8500 people, aged 7 months to 97 years, who had received at least one dose of the adjuvanted H1N1 pandemic vaccine during the national pandemic influenza vaccination campaign in the UK.

The observed number of adverse events of special interest was below the expected number for Bell’s palsy, Guillain-Barré syndrome, and demyelination, but above the expected number for neuritis (1 case within 31 days), and convulsions (8 cases within 181 days).

A meta-analysis of swine flu studies from 19 countries found that between 20% and 27% of the population showed antibodies consistent with swine flu infection within a year of the start of the pandemic in 2009.

The results varied significantly by age. The infection rates were highest in children aged 5–19 years (39% to 55%) and 0–4 years (30% to 43%), while 8% to 24% of people older than 65 had some preexisting immunity.