Immune evasion of COVID-19 variantsMarch 6, 2021
Several governments and researchers have highlighted the advantages of herd immunity and mass vaccination as potential strategies to tackle the COVID-19 pandemic. However, immune evading SARS-CoV-2 variants may become a major challenge to this approach. This means we must re-evaluate our approaches and public health strategies to create new methods. Several studies suggest that the emergence of new variants does correlate with reduced immune protection after the initial or first exposure to a virus or a vaccine. The evolution of immune evasive mutants was observed in the case of several other viruses and is usually associated with the waning of the human immune response, primarily antibody response. The most important aspect in the case of SARS-CoV-2 is the rate of appearance of such mutations in several countries like the UK, South Africa, Brazil and now India. The potential dynamics of natural or vaccine immunity may put increased pressure on the viral ecosystem, leading to these mutants with increased transmission capability and immune evasion. Of course, even in case of immune evasion, present vaccines may provide a certain amount of protection to individuals, though it may lead to reduced chances of herd immunity. This situation now poses several serious questions not only around our vaccination strategy, but also on the treatment, prevention and control strategies.
People around the world have been patient and are waiting for this global health crisis to end. Therefore, it is important to take steps which are not based on confinement or lockdowns. The impact of such steps has already led to an economic crisis, with more to come in the future. In particular, the confinement of younger people has resulted in a rise in unemployment and debt. A proper strategy, which incorporates social monitoring and enables the containment of local infections, is the need of the hour. Some of the important steps in this regard would include technologies to monitor the air for aerosols in enclosed areas like transport systems, offices, schools and hospitals. An integrative approach involving the use of technology to curtail the spread of the virus will help avoid major losses to the economy and the people.
Other aspects of the approach can include the continued use of masks and social distancing and the voluntary self-isolation of older populations to reduce the risk of contracting the virus. Governments must encourage adherence to the rules for the protection of such groups. These steps, in conjunction with vaccination for the majority of the population, can help in protecting the population at large. It is also important for scientists and governments to develop improved drug development pipelines, in addition to the present vaccination capabilities. A focus on the development of peptide-based viral inhibitors will also be a crucial and important step in countering the pandemic. The multi-valent peptides under development to stop the virus from binding to the cell surface and multiplying can be used as prophylactic and therapeutic approaches.
The author is a medical scientist and former director of SGRF, Bangalore