缅北禁地

For a century, epidemics of meningococcal A meningitis, a bacterial infection of the lining of the brain and spinal cord, have swept across 26 countries in sub-Saharan Africa killing and disabling young people every year. The disease is highly feared on the continent it can kill or cause severe brain damage within hours.

But just 5 years after an affordable meningitis A vaccine was introduced, its use has led to the control and near elimination of deadly meningitis A disease in the African 鈥渕eningitis belt.鈥� In 2013, only 4 laboratory-confirmed cases of meningitis A were reported by the 26 countries in the belt, which stretches across the continent from Senegal to Ethiopia.

The meningitis A vaccine for Africa, MenAfriVac, was developed in response to a plea for help from ministers of health in sub-Saharan Africa after an outbreak of meningitis A in 1996 infected over 250 000 people and killed over 25 000 in just a few months. The vaccine costs less than US$ 0.50 a dose and wherever it has been rolled out, meningitis A has disappeared.

Eliminating a deadly disease with routine immunization

鈥淲e have nearly eliminated meningitis A epidemics from Africa, but the fact is the job is not yet done,鈥� said Dr Jean-Marie Okwo-Bele, Director of Immunization, Vaccines and Biologicals at WHO. 鈥淥ur dramatic gains against meningitis A through mass vaccination campaigns will be jeopardized unless countries maintain a high level of protection by incorporating the meningitis A vaccine into their routine childhood immunization schedules.鈥�

The findings are reported in a special collection of 29 articles in the journal "Clinical Infectious Diseases" 鈥攚ith guest editors from the former Meningitis Vaccine Project, a partnership between WHO and the international health non-profit organization, PATH. The supplement, titled 鈥淭he Meningitis Vaccine Project: The development, licensure, introduction and impact of a new Group A meningococcal conjugate vaccine for Africa,鈥� was sponsored by the Bill & Melinda Gates Foundation.

In the opening article of the supplement, WHO Director-General, Dr Margaret Chan, together with public health leaders from PATH UNICEF Gavi, the Vaccine Alliance the Bill & Melinda Gates Foundation and the vaccine manufacturer Serum Institute of India, among others, called the vaccine a 鈥渟tunning success.鈥� As of today, the vaccination campaigns reached more than 237 million people aged 1 through 29 years in 16 countries (Benin, Burkina Faso, Cameroon, Chad, C么te d鈥橧voire, Ethiopia, Gambia, Ghana, Guinea, Mali, Mauritania, Niger, Nigeria, Senegal, Sudan, and Togo). Of the 26 countries in the African meningitis belt, 10 still need to fully roll out vaccination.

鈥淥ur partnership allowed us to develop an affordable, tailor-made vaccine for use against meningitis A in sub-Saharan Africa in record time and at less than one-tenth the cost of a typical new vaccine,鈥� said Steve Davis, president and Chief Executive Officer of PATH. 鈥淭he global community should not risk squandering this amazing lifesaving investment.鈥�

Long-term protection

Before 2010, meningitis epidemics were becoming more frequent and widespread throughout Africa, placing a great burden on individuals, families, and the health systems of affected countries.

MenAfriVac was introduced as an improvement over older polysaccharide vaccines, which can only be used after epidemics have started, do not protect the youngest children or infants, do not alter disease transmission and provide only short-term protection. Scientists found that 90% of individuals who were vaccinated with MenAfriVac still had protective antibodies in their system 5 years later. Studies show that this is a good predictor of even longer-term protection that scientists will continue to track.

An added benefit is that the vaccine also boosts protective immune responses to tetanus, a painful bacterial disease that can cause involuntary muscle tightening and spasms sometimes strong enough to fracture bones. Tetanus cases in newborn babies have fallen by 25% in countries that completed Meningitis A campaigns in 1 through 29 year olds, according to one of the studies in the collection.

Sustaining protection in countries is essential

鈥淐ountries now need to decide how best to sustain the protection that initial mass vaccination campaigns provided,鈥� said Dr Marie-Pierre Preziosi of WHO, a member of the team that developed the vaccine. 鈥淥ur experience from other vaccine-preventable diseases has shown that if we let our guard down, these diseases will severely rebound.鈥�

A modelling study has shown that if no subsequent immunization programme was implemented after a large one-off vaccination campaign, countries could expect to see 鈥渃atastrophic resurgences in disease鈥�, after approximately 15 years.

鈥淭he world came together to create tremendous health impact with this vaccine,鈥� said Dr Marc LaForce, who worked on the development of the meningitis A vaccine. 鈥淲e need to ensure that we finish the job with meningitis A and apply the lessons learned to the next generation of meningitis vaccines for Africa.鈥�