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Vaccines Don't Save Lives, Vaccination Does
Published in Norman Begg, The Remarkable Story of Vaccines, 2023
Although most vaccines have been developed by the big multinationals, there are exceptions. For more than a century, epidemics of meningitis have swept across sub-Saharan Africa. The epidemics start in January, as hot dry winds blow sand southwards from the Sahara Desert, and stop abruptly when the rains arrive, usually in June. The so-called meningitis belt has the highest incidence of the disease in the world by far. Nearly all of the cases are caused by one strain of the meningitis bacterium, group A. The Meningitis Vaccine Project was established in 2001 with funding from Bill Gates, to develop a vaccine specifically for the meningitis belt. This is a partnership between WHO and PATH (Programme for Appropriate Technology in Health). The vaccine, which is manufactured by the Serum Institute of India, reduced the rate of disease by ninety-four percent, and in countries that have conducted mass vaccination campaigns, the disease has all but disappeared. The meningitis belt vaccine – MenAfrivac – sells for under ¢50 a dose.
Understanding barriers to vaccination against invasive meningococcal disease: a survey of the knowledge gap and potential solutions
Published in Expert Review of Vaccines, 2023
Isabella Ballalai, Rob Dawson, Michael Horn, Vinny Smith, Rafik Bekkat-Berkani, Lamine Soumahoro, Nevena Vicic
While the use of meningococcal vaccines has led to substantial declines in both carriage and incidence of disease globally, IMD remains a global public health concern [15]. For example, by the end of 2020, the conjugate vaccine for N. meningitidis serogroup A (MenAfriVac) had been administered to almost 350 million people in 24 of the 26 countries in the African meningitis belt [20]. Prior to the introduction of this vaccine, serogroup A caused 80–85% of meningitis epidemics in the African meningitis belt [20]. Surveillance data showed that MenAfriVac introduction led to substantial reductions in the incidence of suspected meningitis (57%) and epidemic risk (59%) in vaccinated vs unvaccinated populations, as well as a > 99% reduction in confirmed serogroup A disease in fully vaccinated populations within nine countries between 2005 and 2015 [21]. For adolescents aged 13–17 years in the USA in 2020, the estimated meningitis A, C, W, and Y (MenACWY) vaccine coverage was 89% for ≥ 1 dose and 54% for ≥ 2 doses [22]. For adolescents aged 17 years in the USA in 2020, only 28% had received ≥ 1 dose of the MenB vaccine [22]. As such, much remains to be done in terms of improving IMD awareness and vaccine coverage globally.
Recent advances in freeze-drying: variables, cycle optimization, and innovative techniques
Published in Pharmaceutical Development and Technology, 2022
Mohammed M. Mehanna, Kawthar K. Abla
On top of improving shelf life, lyophilizing the pharmaceuticals further eliminate their volumes and weights, assisting cut down on shipping costs and environmental pollution risk. Reducing the requirements for shipping procedures designed to maintain the stability of product as dry ice, and facilitates logistics. These features are specifically important when transporting products among developing countries with limited budgets. Long distances during transportation and often hot environment would otherwise create a significant strain on cold chain transport. With lyophilization, a temperature-controlled chain is not necessary. An example of this, is the freeze-dried vaccine. ‘MenAfriVac’, for example, was licensed for use in sub- Sahara Africa for children and adults against meningococcal bacterium meningitides group A, where accessibility for cold chain maintenance is limited. It was the first vaccine that gained approval to be transported outside the cold chain, with exposure to temperatures up to 40 °C for up to 4 d is acceptable (Steffen et al. 2014).
Antibody persistence following meningococcal ACWY conjugate vaccine licensed in the European Union by age group and vaccine
Published in Expert Review of Vaccines, 2020
Weichang Luo, Peter D. Arkwright, Ray Borrow
This literature review compares the immunogenicity and antibody persistence in different age groups and doses between the MenACWY-TT and MenACWY-CRM197 on the serogroups A, C, W, and Y, but not serogroup B, the most common serogroup caused IMD in European countries and the most difficult serogroup to design an effective vaccine. In September 2015, the UK National Immunization Schedule introduced the four-component capsular group B meningococcal vaccine (4CMenB) to infants for 3 doses at 2, 4, and 12 months of age [44]. This vaccine against serogroup B IMD has now proved to be effective but antibody persistence studies are required to determine the duration of protection [45]. Serogroup A was the most common serogroup that causes MD in sub-Saharan Africa. MenAfriVac is a serogroup A meningococcal polysaccharide-tetanus toxoid conjugate vaccine, it has been licensed for those aged at 1 to 29 years in countries across the African meningitis belt. Studies have shown that antibody levels assessed by SBA titers were more persistent in people between the ages of 2 and 29 years then those under 1 year of age [46]. The greater the antibody level pre-vaccination, the higher the immunogenicity and antibody persistence after vaccination. In a study of Yaro et al. [47], the relative change in geometric mean antibody level in the 2016 survey was greater among younger groups in the different age groups of 6 to 29 years of age compared to 2011. Since the introduction of MenAfriVac, a significant reduction in serogroup A invasive disease has brought hope for the elimination of MD outbreaks in sub-Saharan Africa.