Africa's largest measles vaccination campaign could reduce childhood mortality by 20%

After years of declining immunization rates, a nationwide measles vaccination campaign in Kenya, the largest ever to be undertaken in Africa, was judged "very successful" by Minister of Public Health Sam Ongeri. "From a target population of 13.6 million the number immunized was 13.3 million, a record coverage of 98%" he said. In the year 2000 coverage was just 60%.

Rudi Eggers, WHO Inter-Country Epidemiologist for Eastern Africa, told the Bulletin that "more than 85% coverage is needed to protect against a measles epidemic. We need to have a herd immunity effect". In other words, the few unimmunized people need to be far enough apart so that transmission cannot continue. "For measles this is quite a big task, as this is quite an infectious disease. So you actually need to reach very high coverage — 98% or so — to get that herd immunity. It seems that Kenya has reached that figure. We did a coverage survey after the campaign, to get some independent verification of that data" said Eggers.

The biggest remaining uncertainty, however, is not the number vaccinated but the census — how many people there actually are in the country. And mopping up now needs to be done in areas that did not reach the target level.

Measles in Kenya is still a severe disease. Some 10% of cases develop complications including convulsions, inner ear infections, pneumonia, diarrhoea and inflammation of the brain. "Survivors are often left with lifelong disabilities including blindness and brain damage" said Ongeri. Yet over the last three years, Kenya had seen a fall in measles immunization coverage. It was estimated that 18 000 children were dying each year from measles in Kenya. Directly and indirectly, measles was contributing 20% of the mortality rate in children under five years of age.

Nicholas Alipui, the UNICEF country representative, said that with the success of the campaign in Kenya, doors were opening for other African countries to undertake similar campaigns. "Measles has been and continues to be a highly contagious infectious disease throughout the world" said Alipuli. "UNICEF continues to stand behind the Ministry of Health, to use resources accrued from this campaign to strengthen routine vaccination in private and public health facilities." With a concerted effort, he said, it would be possible for Kenya to have no measles deaths in a few years.

The Kenyan Minstry of Health organized the vaccinations and ran this campaign, while WHO and UNICEF gave in-country support. The main funders were the US Centers for Disease Control, the UN Foundation and the American Red Cross. Eggers added, "A group called the Measles Initiative has solidified around those three funders, and now has US$ 20 million in the kitty to do more campaigns. We are planning for all of East Africa to be doing similar campaigns in due course".

Catherine Wanyama, Nairobi