The COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to be a global health concern. At the time of writing, the number of diagnosed cases around the world has exceeded 194 million with Asia recording over 60.5 million.
At the end of 2020, the emergence of fast-spreading SARS-CoV-2 mutant strains (B.1.1.7, B.1.351, and B.22.214.171.124) has created more concern for the prevention and treatment of COVID-19. It is speculated that the emergence of the SARS-CoV-2 variants may portend a new phase of the pandemic.
However, these rising numbers mean that researchers have also gained increased experience in preventing and treating COVID-19 through virological, immunological, epidemiological, and clinical investigations of this disease.
The SARS-CoV-2 virus genome is made up of almost 30,000 nucleotides; molecules that contain instructions for the amino acids that make up its proteins. But as with all viruses, this genetic code is not set in stone.
When the virus infects a cell, it generates thousands of copies of itself and sometimes makes errors in the process. Most of these mistakes, or mutations, are harmless and do not lead to huge changes in how the virus infects and spreads through the population.
But sometimes these genetic changes can help the virus stay one step ahead, leading to variants that are more contagious and easily spread. Given the continuous evolution of the virus that leads to SARS-CoV-2 and the constant developments in our understanding of the impacts of variants, these working definitions may be periodically adjusted.
When necessary, variants not otherwise meeting all criteria outlined in these definitions may be designated as VOIs or VOCs, and those posing a diminishing risk relative to other circulating variants may be reclassified, in consultation with the WHO Technical Advisory Group on viral evolution.
1. Variants of concern (VOC)
A SARS-CoV-2 variant that meets the definition of a VOI and through a comparative assessment has been demonstrated to be associated with one or more of the following changes at a degree of global public health significance:
The current designated VOCs include B.1.1.7 (Alpha), B.1.351 (Beta), B.1.617.2 (Delta), and P.1 (Gamma).
2. Variants of Interest (VOI)
A SARS-CoV-2 variant with genetic changes that are predicted or known to affect virus characteristics such as transmissibility, disease severity, immune escape, diagnostic, or therapeutic escape. It is also identified to cause significant community transmission or multiple COVID-19 clusters, in multiple markets with increasing relative prevalence alongside the increasing number of cases over time, or other apparent epidemiological impacts to suggest an emerging risk to global public health.
The current designated VOIs include the B.1.526 (Iota), B.1.525 (Eta), B.1.617.1 (Kappa), C.37 (Lambda).
While vaccination is being carried out globally, the emergence of multiple SARS-CoV-2 variants and whether the vaccines’ effectiveness will be impacted have become the core issues in global discussions. Present investigations demonstrated that SARS-CoV-2 variants substantially affect the efficacy of COVID-19 vaccines.
The mRNA vaccine from Pfizer was the first approved COVID-19 vaccine. Shi et al. assessed the neutralization of BNT162b2 vaccine-elicited sera by using engineered mutant viruses. The three engineered variants, including the N501Y variant, 69/70-deletion + N501Y + D614G variant, and E484K + N501Y + D614G variant, showed minimal effect on neutralization of twenty BNT162b2 vaccine-elicited sera.
Moreover, Nussenzweig et al. investigated the antibody and memory B cell responses in 20 participants who received either mRNA-1273 vaccines or BNT162b2 vaccines. They found that the neutralizing activity of vaccine-elicited sera against pseudoviruses (E484K, N501Y, and K417N-E484K-N501Y combination) was reduced.
The biotech firm Novavax recently disclosed the results of phase III clinical trials of NVX-CoV2373 for variants. The protective efficacy to 501Y. V1 (B.1.1.7) and 501Y. V2 (B.1.351) is different. The effectiveness against 501Y.V1 is more than 85 percent and the efficacy against 501Y. V2 is less than 50 percent. This finding indicated that SARS-CoV-2 variants also challenge recombinant protein vaccines.
In general, the available data has indicated that the variant of SARS-CoV-2 may have the ability to resist vaccine-induced immunity. These studies suggest that we should try to update the therapeutic strategy and vaccine design against the challenges of new variants.
DKSH provides physicochemical characterization tools that are used from the initial characterization of biological material such as virus and virus-like particles through to final manufacturing and quality control services. We help to deliver information essential from fundamental vaccine research and characterization through to formulation and process development and into the monitoring of production, process, and lot consistency.
Speak with us to find out more on how your business can keep track of the emergence of these fast-spreading SARS-CoV-2 mutant strains and support in helping the world overcome this pandemic.
Ruethaitip Tiratrakulvichaya has been with DKSH in Thailand since 2009. As the Application Manager for the Malvern product range, she is responsible for technical and application support across Southeast Asia.
With a background in food science and agroindustry, she is experienced in delivering training to both internal colleagues and external customers on how to operate and obtained the best data.
Ruethaitip has extensive working knowledge in material characterization techniques including laser diffraction, dynamic light scattering, micro-calorimetry, size exclusion chromatography and morphological property.