Hundreds of thousands of African children and young adults have been killed or permanently disabled by meningitis A. Following infection, one in ten infected die within days, even when antibiotics are available. One in four survivors are left with permanent disabilities including paralysis, blindness, and hearing loss.
In 1996 and 1997, one of the largest meningitis epidemics in African history caused 250,000 new cases of disease. In the years following this massive outbreak, the World Health Organization (the “WHO”) met with representatives from eight African countries to develop strategies to contain the spread of the disease. The resulting partnership, formed in 2001 with $70M in funding from the Bill and Melinda Gates Foundation, worked with a consortium of international partners to develop MenAfriVac.
MenAfriVac protects people 1 to 29 years of age against meningococcal bacterium group A. Importantly, MenAfriVac developers took into account the realities and shortcomings of the vaccine distribution infrastructure, notably reliance on the “cold chain”. MenAfriVac is the first mass vaccination program in Africa that does not depend on or require constant refrigeration.
About the “Cold Chain”
Changes in temperature degrade vaccines and other protein-based compounds by altering their molecular structure. More than 90% of all vaccines require a temperature-controlled supply chain (the “cold chain”) – without a constant temperature in a very narrow range above freezing, many vaccines lose their potency, become ineffective, or can become hazardous.
Maintaining the cold chain in areas with tropical heat, limited resources, and spotty access to electricity presents a challenge to vaccine developers. According to the World Bank, only 24% of the population of sub-Saharan Africa has access to electricity. Those with access experience unreliable service – African manufacturers report power outages on average 56 days per year.
A break in the cold chain can reduce the efficacy or potency of a vaccine and in some cases can lead to toxicity. In addition to maintaining the cold chain, there is a separate challenge of verifying any lapses in the chain and in testing the viability of the vaccine before it is administered – this can be a challenge even in industrialized countries like the U.S. and Canada.
MenAfriVac Thermostability Studies
MenAfriVac is a lyophilized vaccine of purified meningococcal A. The lyophilization (freeze-drying) process contributes greatly to MenAfriVac’s stability. In October 2012, MenAfriVac received approval from the WHO to be kept outside of the cold chain for up to four days at up to 40°C in a controlled temperature chain (“CTC”). A card with a heat-sensitive sticker accompanies vaccine carriers to monitor temperature excursions.
A 2014 study published in the journal Vaccine assessed the feasibility of using the CTC approach in rural Benin. 155,000 were vaccinated using MenAfriVac. During the campaign, only nine vaccine vials were discarded after exceeding temperature guidelines.
Moreover, vaccinators were able to vaccinate more people and did not need to return to a health center with refrigeration every night, reducing the logistical burden. 98.7% of supervisors and 100% of vaccinators supported the program, preferring to conduct their next campaign using a CTC approach. In 2013, no cases of meningitis A were reported in Benin.
A separate study by the WHO showed that cutting out the cold chain at district-level distribution points could reduce costs by as much as 50%. The 2011 study examined costs incurred during a mass vaccination campaign in Chad where the cold chain was used throughout.
The cold chain requires ice packs, refrigerators, and freezers, as well as kerosene, or an alternative energy source, to keep the refrigerators running. Additional costs are incurred when vaccines, cold boxes, and fresh ice packs need to be replenished. This is particularly challenging in remote areas.
To date, over 153M Africans have been vaccinated against meningitis A. By 2020, the vaccine is expected to protect more than 400M people. The MenAfriVac program already appears to be showing significant reductions in disease – a 2013 report by the WHO indicates that meningitis A cases are at their lowest level in ten years.
VBI’s LPV™ Thermostability Platform
VBI’s LPV™ Platform enables the development of vaccines and biologics that can withstand storage or shipment at constantly fluctuating or elevated temperatures. Once commercialized, this technology could increase vaccine safety, efficacy, and access.
VBI’s LPV™ Platform creates lipid vesicles (small lipid bubbles) which surround and enclose the antigen (active component) of a vaccine. These structures are then ‘freeze-dried’ in a process designed to improve vaccine stability. VBI has previously demonstrated proof of concept studies on a number of vaccine and biologic targets including influenza (one year at 40° C), rabies (18 months at 40°C), and MMR (eight weeks at 40° C).
VBI’s LPV™ technology allows for rapid reformulation of existing vaccines and vaccines in development, making VBI an attractive potential partner for forward-thinking developers. To learn more about the LPV™ Platform, visit: https://www.vbivaccines.com/technology/thermostable-platform/