Rubella immunisation of men: advantages of herd immunity

Abstract

SIR—Gonasekera and Gonasekera (June 15, p 1694) propose that a lesson should be learned from the experience of developed countries and that the managers of expanded programmes of immunisation should consider immunising men against rubella. Immunisation of men in developed countries has been an important step forward in the control of rubella. The results obtained in the province of Gipuzkoa, Basque Country, Spain (population 682 883) emphasise the advantages of herd immunity. Since 1981, rubella vaccination in the Basque Country has included children of both sexes (12–15 months old) and 11-year-old girls. Since 1985, vaccination coverage in both populations in Gipuzkoa was around 90%, with a consequent drop in the incidence of rubella. No cases of congenital rubella have been detected in Gipuzkoa in the past fifteen years. To measure the effectiveness of immunisation policies, a seroepidemiological study was done in 1991 which found a gap in rubella immunity in children born around 1978–82— about 40% were susceptible to infection. The health authorities were informed of the need to prevent future outbreaks among this sector of the population, who could be a source of infection to susceptible women of childbearing age (about 1%). Since 1992, administration of the second dose of the rubella immunisation (as measles, mumps, and rubella immunisation) to 11-year-old girls was extended to include boys. This measure did not include children over 11 years of age, leaving unimmunised many of the boys responsible for the gap. As a result of this lag in herd immunity, there have been two outbreaks of rubella in the past 5 years. The first was in 1992 (annual incidence: 58 per 100 000 people) largely affecting adolescent boys living in coastal regions. This year, there was a widespread outbreak which started inland and later spread to the rest of the province. During the first 6 months of 1996, there were 188 confirmed cases, a small percentage of the true figure, as only a few cases were serologically confirmed and many others were subclinical or unrecognised. Most cases were in males (93·1%), 69·9% of whom were born in 1977–81. In the 1992 outbreak, a woman in her first trimester of pregnancy was infected and her pregnancy terminated. Among the confirmed cases in the outbreak detected this year, six were in women of 20–41 years old, but fortunately none were pregnant. Circulation of the wild rubella virus, whether in women or men, represents a potential risk for pregnant women who are not immune to rubella. The price to be paid should a congenital infection appear is undoubtedly higher than the available in all hospitals, and the emphasis should shift from surveillance for HIV infection to the diagnosis of AIDS.