The war against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19, is in a deep crisis. As confirmed COVID-19 cases surpass 200 million worldwide, we are confronted by news of fast-spreading COVID variants that are leading to new surges in many countries. Ribonucleic acid (RNA)-based viruses such as SARS-CoV-2 can freely change their genetic content. Because they lack a mechanism for repairing a mismatch as they replicate, many variants are produced. A tiny handful of such variants end up conferring an advantage such as being more contagious, which allows them to spread and confound many current measures.
In this article, we describe the classification of disease variants, explain what factors contribute to their prevalence, address the implications for current treatments, and review how best the world can respond.
Should we worry about the new COVID-19 variants?
YES! We should worry. Reports on a fast-spreading COVID-19 variant emerged in December 2020, forcing the World Health Organization (WHO), the United States, and other partners to start a global variant classification system. As new variants pop up, they are classified as either Variants of Interest, Variants of Concern, or Variants of High Consequence.
Variants of Interest:
Variants of Interest (VOIs) have specific genetic changes that reduce the neutralization effects of antibodies generated from current vaccines, which can lower the efficacy of treatments and diagnostics and increase the rate of transmission and disease severity. Examples include Eta (B.1.525), Iota (B.1.526), and Kappa (B.1.617.1).
Variants of Concern:
Variants of Concern (VOCs) have attributes of VoIs and evidence of deadly resistance to the immunity developed by the current vaccines against COVID-19. Examples include Alpha (B.1.1.7), Beta (B.1.351.3), Delta (AY.3), and Gamma (P.1.2).
The Delta variant, first reported in India, is highly contagious. Delta is 60% more transmissible than the Alpha variant. A recent Chinese study confirmed the claim of increased transmissibility. The Delta variant has spread to many countries across the world and is wreaking havoc across the United States, accounting for a very high percentage of all new cases. In the United Kingdom, it was reported to account for about 99% of all new cases as of August 6.
Variants of High Consequence:
Variants of High Consequence (VoHCs) have attributes of VOCs with clear evidence of significant reduction in the effectiveness of current prevention measures or medical countermeasures. So far, no COVID-19 variants qualify to the level of high consequence.
What causes COVID-19 variants?
COVID-19 is unleashing an array of variants because most of the world’s population remains unvaccinated. According to CDC Director Dr. Rochelle Walensky, “we know that the Delta variant…is currently surging in pockets of the country with low vaccination rates.” She also noted that, in the United States, 97% of those currently hospitalized with COVID-19 are unvaccinated. Globally, the Delta variant is spreading like “bush fire,” especially among populations with low vaccination rates, including in countries with early but incomplete adoption of vaccines such as the United States, United Kingdom, and Israel.
How do variants stack up against COVID-19 vaccines?
Even current vaccines such as those developed by Pfizer-BioNTech, Moderna, and Johnson & Johnson (J&J), though effective against the scourge, have no exhaustive proof against harmful effects. Most vaccines are based on the spike protein of COVID-19, but evidence is emerging that new variants with changes in their spike proteins are more deadly and spread faster.
Furthermore, in July 2021, protection by the vaccines differed, including efficacy rates of more than 67% for the J&J vaccine, 72% to 95% for the Moderna vaccine, and anywhere from 42% to 96% for the Pfizer-BioNTech vaccine.
Although determining the effectiveness of each vaccine against the Delta variant remains a challenge, in a few studies, a single dose offered mild protection against the Delta variant, although a second dose was more effective. In May, a single dose of the Pfizer-BioNTech vaccine had 33% protection against the Delta variant, while a second dose increased the protection to 88%. Similarly, single doses of Moderna, J&J, and Astrazeneca vaccines had reduced protection against the Delta variant, which increased with the second dose, but exact efficacy rates for the Delta variant remain difficult to confirm.
Since disrupting the cycle of spread relies on preventing infection of unvaccinated people and then mutations, we must maintain vaccines with a high degree of efficacy and continue vaccinating populations in every affected country around the world.
Are variants complicating COVID-19 treatment?
Three antibody treatments are being used to treat COVID-19: bamlanivimab plus etesevimab, casirivimab plus imdevimab, and sotrovimab. However, clinical data on the susceptibility of emerging variants are lacking. Current laboratory studies show that COVID-19 variants are less susceptible to bamlanivimab and may have reduced sensitivity to etesevimab and casirivimab. So far, many variants are still susceptible to sotrovimab.
What global response should we prioritize?
Only ten countries access 75% of all current vaccines, hence WHO suggests a strategic preparedness and a response plan to accelerate production and access to the vaccines. Such global priorities should align to the following measures:
- Innovative scientific approaches such as randomized vaccine schedules and observational studies that assess the current vaccines, as well as developing modified and new vaccines.
- Science-based public health measures that prevent the escalation of additional VOCs, especially promoting practices that reduce viral transmission and misuse of treatments.
- Effective coordination and collaboration between the WHO, governments, and various research groups. We need stronger coordination to support rapid identification of viral VOCs, selection of antigens for modified and new vaccines, and sharing of research breakthroughs.
Conclusions:
The emergence of new Variants of Concern threatens to reverse achievements against the COVID-19 pandemic. VOCs such as Delta can be transmitted faster among unvaccinated people with more severe outcomes, including longer hospitalizations and increased mortality. Should these attributes escalate, current diagnostics, treatments, and vaccines are going to be less effective — as we are already seeing play out.
Our concern should therefore focus on how to prioritize and implement innovative scientific approaches to de-escalate the rise of new VOCs, as well as how to improve the coordination of a mix of global response measures including vaccines, treatments, diagnostics, tracking of variants, and social measures against the pandemic.
The expansion of the capacity of laboratory diagnosis across the globe is vital to provide enough clinical data on what is happening, to detect novel VOCs faster and respond accordingly. Therefore, to have equitable access to effective vaccines, treatment, and diagnostics we should support a well-balanced preparedness and a response plan for COVID-19 that takes into consideration both rich and poor countries alike.
