Editorial: Misplaced vaccine safety fears

Published in The Hindu on September 5, 2009

Since its outbreak in April, the influenza A(H1N1) virus has spread to many countries and become the dominant influenza strain round the world. According to the World Health Organisation, the pandemic virus is expected to persist in the coming months. Over 200,000 laboratory-confirmed cases of infection and above 2,200 deaths have been reported from across the globe. It is to halt this spread that pharmaceutical companies have embarked on a mission to find a preventive vaccine. The first of several vaccines for H1N1 is expected to be available by October. Although fast-tracking human clinical trials is appropriate in a pandemic situation, there is growing concern about the safety of the vaccines among the medical fraternity, which has been identified as an at-risk group eligible to receive the vaccine as a priority. A survey conducted recently in Hong Kong found that over half of the 8,500 healthcare workers were unwilling to be vaccinated against influenza A(H1N1) owing to fear of the vaccine’s side-effects and doubts about its effectiveness. A poll of nurses in the United Kingdom found that a third of them refused to be vaccinated for the same reasons. While Germany is awaiting the clinical trial results before deciding on its course of action, France is looking up to the European Medicines Agency for advice.

A complete clinical evaluation is the best option but it becomes difficult in the case of influenza because the virus keeps changing continuously. While the effectiveness of H1N1 vaccines is not fully known, there is some evidence of its safety from initial testing on a small scale in the United States and Britain. Reassurance comes from the European Commission, which has approved four mock-up vaccines for H5N1 (avian flu) based on safety and immune response data from trials on 8,000 people. According to the European Medicines Agency, decades of experience with seasonal influenza vaccines indicate that insertion of a new strain in a vaccine, as will apply with the change from H5N1 to H1N1 should not substantially affect the safety or level of protection offered. The U.S. regulatory authority essentially shares this view. The lessons learnt during the SARS outbreak ought not to be forgotten. At one point during the outbreak, 41 per cent of those affected in Singapore and 22 per cent in Hong Kong were healthcare workers. Apart from protecting themselves, vaccinated physicians are less likely to infect others patients. A healthcare breakdown during an epidemic owing to absentee doctors and healthcare workers is a horrifying prospect that should be averted at all costs.