§ Mrs. Wiseasked the Secretary of State for Social Services what information he now has about the efficacy of influenza vaccination.
§ Dr. OwenField trials over a number of years have established that influenza vaccination in general gives short-term protection to about 70 per cent. of persons vaccinated. However, influenza viruses are subject to changes in their antigenic properties which may either be gradual or sudden. To cope with these changes it is usually necessary to modify the vaccine each year to meet the challenge expected during that year.