Scientists are indicating that children in Burkina Faso who were vaccinated against group A meningococcal meningitis and septicemia (MenA) between the ages of 1-4 years in 2010, could need a booster dose of the vaccine as early as this year to ensure they remain protected.
In a study published today in Clinical Infectious Diseases, funded by Meningitis Research Foundation, scientists share new information about the duration of protection that a conjugate meningococcal A vaccine provides, depending on the age at which a person was first vaccinated.
These findings may also help evaluate protection from similar meningococcal vaccines in future.
A number of countries in sub-Saharan Africa - collectively known as the meningitis belt - have been repeatedly devastated by overwhelming epidemics of meningitis and septicemia.
Fortunately, since the introduction of the conjugate vaccine MenAfriVac® in 2010, over 265 million 1-29-year-olds living in the meningitis belt have been vaccinated to protect them against MenA, and there has been a dramatic decline in cases of MenA which was previously the main cause of outbreaks.
Scientists conducted three surveys after the MenAfriVac® campaign in Burkina Faso, one of the countries where the vaccine was first introduced, to assess how well the vaccine was continuing to protect people in the years after the MenAfriVac® campaign. Each survey involved around 600 participants aged from six months to around 30 years. Blood samples were taken from each participant and the time taken to return to pre-vaccination immune levels, measured in the same population in 2008, was estimated.
It was found that people who were aged 1-4 years when they were vaccinated may need a booster vaccination as early as this year, eight years on from the mass campaign. Immunity was retained longer in older age groups.
Study investigator Dr Judith Mueller from the EHESP French School of Public Health in Paris said:
We know that vaccines which help prevent meningococcal disease do not give lifetime protection. The findings from this research provide new insights about when booster vaccinations should be introduced. According to our results, the people who were aged 1-4 years at the time of the vaccination campaign will soon be susceptible to MenA again. They may fall ill if their immunity has worn off, because the bacteria will be given the chance to once again spread and cause disease in the population.
Public health decision makers should take this into account when planning vaccinating strategies to protect people living in the meningitis belt, along with financial and programmatic considerations.”
Vinny Smith, Chief Executive at Meningitis Research Foundation said:
Meningitis and neonatal sepsis combined is the second biggest infectious killer of children under five globally, responsible for more deaths than malaria, AIDS, measles and tetanus put together. This new research shows why routine vaccination is so important in order to prevent meningitis and septicemia in vulnerable groups and gives us a better understanding of when booster vaccinations are needed, to ensure people remain protected. The MenAfriVac® vaccination campaign was unprecedented in terms of its success in controlling the MenA epidemic in Sub-Saharan Africa but protection needs to be maintained and this research indicates that action may be needed urgently.
We are currently funding another research project looking at how long immunity lasts for babies offered the MenB vaccine in the UK. This could give us a greater understanding of the immunity vaccines can provide and when booster doses may be needed. We need to tackle meningitis at a global level to defeat it everywhere.”