THE fall in cot deaths - by more than a third between 1988 and 1991 - may be due to the disappearance of infant welfare clinics, rather than to advice that babies should be laid on their backs rather than their fronts. Doctors from the University's of Keele's Department of Paediatrics argue in the Lancet that the decline began before the campaign for a different sleeping position. They say that in the heyday of infant welfare clinics, up to 90 children, some with respiratory infections, could attend. With more family doctors now involved in child health and fewer infants mixing at clinics, there is less exposure to infection. Improved immunisation for whooping cough may also be a factor.