Five key points about the newest drug for bacterial meningitis

Meningococcal disease is a leading cause of hearing loss, brain damage and limb amputations and, despite the introduction of a highly effective vaccine, remains the second leading cause of infectious death among young children worldwide. The main reason is that the disease is not caused by one type of bacteria, but by several. Today, the world is on the verge of achieving a historic milestone: a vaccine that protects against the five leading causes of this deadly and debilitating disease. Here are five things you should know about it:

1. Vaccination is a very effective strategy against meningococcal disease.

Meningitis is a serious infection of the thin lining surrounding the brain and spinal cord that can cause severe brain damage and be fatal in 80% of cases if left untreated. Several different bacteria may be responsible, but Neisseria meningitis (meningococcus) is responsible for large, deadly outbreaks in a region of sub-Saharan Africa called the African meningitis belt, which has the highest incidence of meningococcus in the world.

The MenFive vaccine is expected to be more accessible to countries in the meningitis belt than existing meningococcal conjugate vaccines that protect against multiple serogroups.

Historically, major epidemics have struck these countries every five to twelve years. But since the introduction of the MenAfriVac vaccine in 2010, the leading cause of epidemic meningitis, group A meningococcus, has been largely eliminated, saving millions of lives.

What made this vaccine so effective is that, unlike previous meningococcal vaccines, the MenAfriVac vaccine binds – or “conjugates” – complex sugars called polysaccharides from group A meningococci to a carrier protein that activates a much wider part of the immune system . resulting in stronger and longer-lasting protection. Conjugate vaccines also prevent bacteria from being carried and passed on to others, helping to protect unvaccinated people through herd immunity.

The problem is that the five other serogroups N. meningitis can cause outbreaks: B, C, Y, W and X. Although conjugate vaccines are available to protect against groups B, C, Y and W, they are not available for routine use in most low-income countries, although they have been used during epidemic outbreaks. Groups C, W and X are also a growing problem in sub-Saharan Africa, and no existing vaccine protects against X.

“We need vaccines to prevent and respond to outbreaks caused by these other groups,” said Professor Caroline Trotter, an infectious disease epidemiologist at the University of Cambridge andImperial College Londonin the UK, and Chairman of the Scientific Advisory Committee of the Meningitis Research Foundation.

2. MenFive protects against the five leading causes of epidemic meningitis in sub-Saharan Africa.

In July 2023, the World Health Organization approved a new meningococcal conjugate vaccine, Men5CV (MenFive), which protects against the five serogroups responsible for almost all meningitis epidemics in sub-Saharan Africa: A, C, Y, W and X.

“As infectious disease outbreaks increase around the world, new innovations like MenFive are needed to help us fight back,” said Dr. Tokunbo Oshin, director of high-impact countries at GAVI, the Vaccine Alliance. “Thanks to vaccines, we have eliminated large, devastating epidemics of meningitis A in Africa: we now have a tool to combat other meningococcal serogroups that continue to cause major epidemics leading to long-term disability and death. »

Importantly, this vaccine is stable at room temperature, which will make it easier to administer and protect in remote communities with little healthcare infrastructure.

Its introduction is planned to enhance the impact of the group A meningococcal vaccine MenAfriVac and is seen as a critical step towards the goal of eliminating epidemic meningitis by 2030.

3. It is more affordable than the already available multivalent meningococcal vaccines.

The vaccine is the result of a 13-year collaboration between the Serum Institute of India and PATH, with funding from the UK Foreign, Commonwealth and Development Office. “Because some of the development costs have been shared and manufacturers have committed to producing meningitis vaccines for use in Africa, this makes them more affordable than vaccines produced by pharmaceutical companies in the Global North,” Trotter said.

With an expected cost of around US$3 per dose, the MenFive vaccine is expected to be more affordable to countries in the meningitis belt than existing meningococcal conjugate vaccines, which protect against multiple serogroups. This means countries are more likely to be able to include it in their routine vaccination programmes.

4. One dose should provide reliable protection against meningococcal infection.

Although the effectiveness of the MenFive vaccine is currently unknown, it has been licensed based on safety and immunogenicity (immune response) data in infants, suggesting it is “non-inferior” to the quadrivalent MenACWY-TT vaccine already used in the US. States since 2005, without noticeable security problems. The previous study also found that it was safe and immunogenic in healthy people aged 2 to 29 years in Mali and Gambia, and that 97% of people who received the MenFive vaccine developed a strong immune response against group X meningococci.

“I think we can be confident that this vaccine will work because we know that MenAfriVac, made by the same company, is very effective, and we know that other multivalent meningococcal conjugate vaccines are very effective,” Trotter said.

5. Widespread prophylactic use of the vaccine is the best strategy to prevent outbreaks from occurring.

In February 2024, Nigeria became the first country to receive doses of the MenFive vaccine from the Gavi-funded emergency stockpile, which provides rapid supply of vaccines for outbreaks of meningitis, yellow fever, cholera and Ebola in low-income countries. These doses will be used to respond to the ongoing outbreak of meningococcus C in Nigeria, which has affected approximately one million children.

However, “although this is the first time it has been used in response to an epidemic in Nigeria, it will indeed have the greatest impact if used as part of prevention campaigns, as recommended by Nigeria’s Strategic Advisory Committee.” Immunization Experts (SAGE) from the World Health Organization,” Trotter said.

WHO has recommended that all countries in the meningitis belt introduce the new vaccine into their routine immunization programs, with a single dose scheduled between 9 and 18 months of age. In high-risk countries and those with high-risk areas, WHO recommended additional catch-up campaigns targeting all young people aged 1 to 19 years. According to WHO, countries already using the group A vaccine MenAfriVac should start switching to MenFive.

Gavi will support these efforts by helping to fund the purchase of MenFive doses for introduction into routine immunization programs and catch-up campaigns in low-income countries at high risk of epidemic meningitis, and for outbreak response. Applications for this support are expected to open during 2024.

While the vaccine is primarily intended to prevent outbreaks of meningitis in African countries, it may have other uses in other countries. “For example, it could also be useful for Hajj pilgrims who need to be vaccinated to protect against meningococcal disease,” Trotter added.