Negligible risk

Sir, - The risk of a healthy recipient of oral polio vaccine getting paralytic polio is only 1 in 6.8 million doses of OPV and not three per cent as mentioned by Dr. Bala N. Aiyer in his letter (TheHindu, Jan. 27). The U.S. discontinued the routine use of OPV last year, only after eliminating paralytic polio with the use of OPV for several years. It discontinued OPV in preference to inactivated polio vaccine (IPV) only after vaccine-associated paralytic polio became the sole case of polio in the country.

The American Academy of Paediatrics still recommends that, ``if an outbreak of wild-type polio-virus infection occurs in the U.S., OPV is the vaccine of choice to control most effectively the spread of infection''. For countries like India, ``the APP continues to support the WHO recommendation for the use of OPV to achieve global eradication of poliomyelitis, especially in countries with continued or recent circulation of wild-type polio-virus''.

Dr. Bala N. Aiyer's comment about the uselessness of BCG may have been based on the conclusions of a recently-published ICMR study. It assessed only the usefulness of BCG in reducing adult pulmonary tuberculosis, and found that it did not have any effect on that. But several other studies around the world have shown that BCG vaccination in early infancy protects children against the severer forms of TB - tuberculous meningitis, miliary tuberculosis and other non-pulmonary TB.

This aspect was not looked for in the ICMR study and it neither proves nor disproves the protective effect of BCG. Hence, although BCG is not a protection against pulmonary tuberculosis, its protective effect on other forms of TB makes it still a useful vaccine especially in India, where tuberculosis is very prevalent.

Rajaji's campaign against BCG might be put in the category of fights against smallpox inoculation and similar forgettable episodes. Had we responded to such misplaced alarms, smallpox would still have been with us. As in any medical remedy, there is no zero-risk option. A minimal risk is the price we have to pay for eliminating several diseases, and as long as the risk from a certain disease far outweighs the risk from immunisation, the vaccines should be continued.

In India the risks from polio are much higher than from the consequences - which are rare - arising from the use of OPV.

Alexander Mathew,

Kochi

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