A method to extend the shelf-life of the vaccines.
Recently, the news about Nipah virus claiming numerous lives in Kerala, shocked us to the core. Our understanding regarding these emerging infectious agents is still developing. On the other hand, fatalities due to infectious microbes, like the Zika virus, the H1N1 virus, the HIV, the influenza viruses etc., are continuously escalating.
Three infectious diseases were ranked in the top ten causes of deaths worldwide in 2016, by the World Health Organization (WHO). 5.4% of total deaths are due to viral exposures.
Vaccine - A vaccine is a biological preparation that provides active acquired immunity against a particular disease. It typically contains an agent that resembles a disease-causing microorganism and often comprises of weakened or killed forms of microbes, their toxins, or their surface proteins. Vaccination is one of the important approaches of protecting ourselves and our future generations from the deadly effects of these viruses.
Vaccines stimulate the body's immune system to recognize the microbe as a threat and destroy it, in the present and future. It also helps to destroy related infectious agents, during subsequent encounters. Although extremely useful and effective, vaccines present some drawbacks, particularly with their stability during storage and transport.
Cases where vaccines have to be transported for long distances, their time of transit may render their cold storage difficult. Such a long time of transit can cause degradation before they may be utilized.
Hence, researchers are focusing their investigations on extending the shelf-life of vaccines. A research group in Canada developed a strategy to increase the stability of vaccines. They protected the vaccines in single-dose containers by coating them with a sugary solution. This solution is known to increase the shelf-life of the vaccines.
This method is analogous to the usage of salt/vinegar for long-term preservation of pickles. These sugar-coated vaccines were stable enough to be transported over long distances. This provided a cost-effective and simple way to improve stability and also extend the transportation time for fragile vaccines.
Moreover, the sugar used for coating did not interfere with the activity of the vaccine upon administration. The sugar coating could be dissolved by adding a sufficient quantity of water. Moreover, the vaccines prepared by this strategy are not affected by temperature fluctuations during transport. This is due to packaging in well-equipped airtight containers and delivery in cold-storage conditions.
This research can prove to help save the lives of thousands of people, living in remote locations.
Indian research work carried out by the authors Mr Ozan S. Kumru, Ms Sangeeta B. Joshi, Mr Dawn E. Smith. This work titled ‘Vaccine instability in the cold chain: Mechanisms, analysis and formulation strategies’ was published in the year 2014 in the domain of Biologicals of Elsevier. The purpose of this review is to create awareness of the scientific and technical difficulties for successful formulation and stabilization of several types of vaccines, both in terms of the stability of antigens, adjuvants and their complexes. Much effort is needed to maintain vaccine activity throughout the cold chain, during clinical advancement and commercialization. A combination of long-term research goals to develop immunogenicity and the internal stability of vaccines, as well as short-term approaches to better utilize the available cooling chain technology for vaccines, is needed. This combined approach will decrease wastage and improve vaccination coverage. It will play an important role in the future development of new vaccines to prevent dissatisfied medical needs due to infectious diseases around the world.
Editor: Dr Prajakta Dandekar Jain
- Vincent Leung, Jonathan Mapletoft, Ali Zhang, Amanda Lee, Fatemeh Vahedi, Marianne Chew, Alexandra Szewczyk, Sana Jahanshahi-Anbuhi, Jann Ang, Braeden Cowbrough, Matthew S. Miller, Ali Ashkar, Carlos D. M. Filipe. Thermal Stabilization of Viral Vaccines in Low-Cost Sugar Films. Scientific Reports, 2019; 9 (1) DOI: 1038/s41598-019-44020-w