Serum Institute of India (SII) has announced it has partnered with UK biotech company, Spybiotech, a spin-off of the University of Oxford, to develop a COVID-19 virus-like-particle (VLP)-based vaccine. The vaccine has entered a Phase 1/2 trial in Australia. In October, another Indian drug maker, Aurobindo Pharma, said it entered into collaboration with Hyderabad-based Centre for Cellular and Molecular Biology (CCMB), a Council of Scientific and Industrial Research (CSIR) lab, to manufacture a COVID-19 vaccine based on VLP.
It isn't SII and Aurobindo Pharma alone, there more than a dozen COVID-19 vaccine candidates currently under development that are based on VLP.
What is VLP?
VLP resembles the SARS-CoV-2 virus. The VLP is constructed incorporating all key structural proteins, mirroring the molecular structure of coronavirus. However, it doesn't cause infection as it doesn't have the genetic material that helps it replicate like a natural virus. VLPs can be produced using mammalian cells, insect cells, bacteria, yeast and plant cells. Animal studies have found out that vaccines based on VLP induce immune response, providing protection against any future COVID-19 infection. To be sure, there are several VLP-based vaccines commercially available including vaccines against Human Papilloma Virus (HPV) and Hepatitis B Virus (HBV). Most licensed VLP vaccines use the aluminum adjuvant to boost their efficacy.
Why do companies consider VLP vaccines?
Frequently Asked Questions
A vaccine works by mimicking a natural infection. A vaccine not only induces immune response to protect people from any future COVID-19 infection, but also helps quickly build herd immunity to put an end to the pandemic. Herd immunity occurs when a sufficient percentage of a population becomes immune to a disease, making the spread of disease from person to person unlikely. The good news is that SARS-CoV-2 virus has been fairly stable, which increases the viability of a vaccine.
There are broadly four types of vaccine — one, a vaccine based on the whole virus (this could be either inactivated, or an attenuated [weakened] virus vaccine); two, a non-replicating viral vector vaccine that uses a benign virus as vector that carries the antigen of SARS-CoV; three, nucleic-acid vaccines that have genetic material like DNA and RNA of antigens like spike protein given to a person, helping human cells decode genetic material and produce the vaccine; and four, protein subunit vaccine wherein the recombinant proteins of SARS-COV-2 along with an adjuvant (booster) is given as a vaccine.
Vaccine development is a long, complex process. Unlike drugs that are given to people with a diseased, vaccines are given to healthy people and also vulnerable sections such as children, pregnant women and the elderly. So rigorous tests are compulsory. History says that the fastest time it took to develop a vaccine is five years, but it usually takes double or sometimes triple that time.
When compared to vaccines that deal with live viruses that require biosafety level-3 containment manufacturing facilities, limiting their ability to scale up rapidly, VLP on other hand require current good manufacturing practices (CGMP)-compliant manufacturing sites. This enables faster scale-up, which is critical during a pandemic. In addition, VLP vaccines can be developed and produced at much shorter timelines of 3–12 weeks, compared to viral vector or whole virion vaccines that need at least six months.
How long will it take to see VLP COVID vaccines?Two VLP vaccines have reached the clinical trial stage. Canadian biotech firm Medicago, backed by tobacco behemoth Phillip Morris, vaccine candidate based on VLP has reached phase 2/3 trial. The vaccine uses plant leaves from the tobacco family to produce VLP. The other Covid-19 vaccine is SII-Spybiotech, which has entered phase 1/2 trial. The VLP vaccines may not be hitting the market any time soon, but they will also be a useful option.