A team of researchers from the Harvard Medical School in Boston, U.S. developed a modular protein subunit vaccine against COVID-19.
The COVID-19 pandemic has caused unprecedented effect on the healthcare and economic structures of countries across the globe. Vaccination is an effective tool in the fight against COVID-19 and due to concerns of new variants vaccination drive should not be delayed. The mass rollout of COVID-19 vaccination in developed countries such as the U.S., the U.K., and others has proved highly effective in controlling SARS-CoV-2 infection. However, there is a limited circulation of vaccines in low- and middle-income countries owing to high costs, insufficient supplies, and cold storage requirements. So, researchers across the globe are trying to develop vaccines to fulfil this unmet demand. In this study, Dr. Dan Barouch and his team of researchers used SpyTag-SpyCatcher, a polypeptide-based system, to covalently link the antigen to the hepatitis B virus like particle (VLP). The researchers developed the vaccine using the linkage system SpyTag-SpyCatcher. The vaccine contains the receptor-binding domain (RBD) of the COVID-19 spike protein or S protein. This RBD is the main target of neutralizing antibodies after vaccination or natural infection. The researchers found that RBD-VLP antigen evoked higher levels of neutralizing antibodies in non-human primates in comparison to other licensed COVID-19 vaccines. The researchers found that the vaccine had the potential to reduce viral loads in the upper and lower respiratory tract of the animals considered for study following challenge with SARS-CoV-2. Moreover, RBD-VLPs spike protein components are produced in yeast which provides a low-cost manufacturing process. New vaccines can be produced by local manufacturers which can decrease the cost required for vaccine distribution. In this context, it is important to mention that this new vaccine is manufactured at the Serum Institute of India.
In a nutshell, this RBD-VLPs vaccines are cost-effective vaccines. These vaccines do not require cold storage and are effective against COVID-19 when used with adjuvants.