Editorial: The oral polio vaccine is safe

Published in The Hindu on December 25, 2008

Ever since four infants died in Tamil Nadu’s Thiruvallur district after they were vaccinated against measles in April 2008, there has been some apprehension about the safety of vaccination. More recently, the death of three children in Tamil Nadu and one child in Karnataka following oral polio vaccination served as grist to the rumour mill. The outcome in Tamil Nadu, according to public health officials, was panic that led many parents to refuse to get their children vaccinated. What is clear is that the polio vaccination had nothing to do with the deaths, which were by other medical causes. It is scientifically established that none of the chemicals used in the vaccine can trigger anaphylaxis. This is an immediate immunological reaction characterised by breathlessness, low blood pressure, and swelling of the body that is encountered extremely rarely (and if encountered, can be easily treated with adrenaline) when a vaccine is administered intramuscularly or subcutaneously. As the polio vaccine is given orally, the chances of death from anaphylaxis are nil. Even if the vaccine were to contain some other live infectious virus instead of the weakened polio virus, it would take a few days for the virus to multiply and reach a critical number to cause an infectious disease. It is inconceivable that two drops of any vaccine can kill a child within a short time, especially when given orally. The only drawback of the oral polio vaccine, which uses a live attenuated virus to induce immunity, is the extremely low risk of inducing polio in 1 in 150,000 vaccinated children.

The number of children vaccinated in Tamil Nadu during the first two days, December 21 and 22, of the programme was a disturbing 300,000 below the number vaccinated during the corresponding days in January, the first round of vaccination for 2008. Since the relevant numbers have remained virtually unchanged year after year from 2004, the substantial drop can be reasonably suspected to be on account of the fear factor. The public health authorities in Tamil Nadu and Karnataka need to work single-mindedly, deploying their scientific imagination and persuasive powers, including the most effective communication tools, to assure people of the safety of the polio vaccine. It is critical for the polio and other vaccination programmes to continue to be accepted by the people. Tamil Nadu, which has not had a single case of polio during the last two years, should go all out to vaccinate every child missed out this time. While the polio vaccine is absolutely safe, it must be remembered that children not vaccinated in time are at risk of getting infected by imported wild virus strains.