COVID-19 (SARS-CoV-2): New virus variants
Studies show that all viruses mutate over time. When a virus replicates, it sometimes changes a little bit – these changes are called “mutations”. A virus with one or more new mutations is referred to as a “variant” of the original virus.
What causes a virus to change to a new variant?
When a virus is circulating widely in a population and causing many infections, it is more likely that it will mutate. The more opportunities a virus has to spread, the more it replicates and changes. Most viral mutations have little to no impact on the virus’s ability to cause infections and disease. However, depending on where the changes are located in the virus’s genetic material, they may affect a virus’s properties (such as transmission rate or severity). Multiple variants of the virus that causes COVID-19 have been documented globally since the onset of the pandemic.
A mutation becomes a “variant of concern” (VOC) when it shows evidence of fulfilling at least one of several criteria, including easy transmission, more severe illness, reduced neutralisation by antibodies or reduced effectiveness of treatment and vaccines.
Experts’ concerns are currently focused on these variants:
Variant 20I/501Y.V1, VOC 202012/01, or B.1.1.7 (Alpha)- first detected in September 2020 and is now highly prevalent in London and southeast England. This variant has an unusually large number of mutations and has been detected in several countries around the world. Variant VOC 202102/02 – first identified in Bristol, is a mutation of B1.1.7 and contains the E484K spike protein mutation, that some experts believe could help the virus slip past the body’s immune defences, and reduce vaccine efficacy.
Variant 20H/501Y.V2 or B.1.351 (Beta) – first emerged in early October in South Africa. This variant shares some mutations with the UK variant and cases have been reported outside of South Africa.
Variant P.1 (Gamma) – first identified in four travellers from Brazil during routine screening at Haneda airport outside Tokyo. This variant contains a set of additional mutations that may affect its ability to be recognized by antibodies.
Variant B.1.617 (Delta) – first found in India in October 2020. According to WHO, preliminary studies show that this variant mutation spreads more easily than the other variants and has already spread to more than 30 countries. Based on current data, WHO states that COVID-19 vaccines remain effective at preventing disease and death in people infected with this variant.
The increase in the number of cases due to these variants of concern has put considerable strain on health care resources worldwide. New information about the virologic, epidemiologic, and clinical characteristics of these variants continues to emerge. Scientists are working to learn more about these variants to better understand how easily they might be transmitted and the effectiveness of currently authorized vaccines against them. The CDC and WHO, in collaboration with other public health agencies continue to monitor the situation closely and information will be communicated as it becomes available.
How can we prevent future new variants of the COVID-19 virus?
Stopping the spread at the source remains key. Rigorous and increased compliance with public health mitigation strategies is crucial to reducing the amount of viral transmission and therefore also reducing opportunities for the virus to mutate. These include:
- Physical distancing and avoiding crowded places or closed settings
- Use of masks as advised
- Good ventilation
- Hand hygiene
- Adhering to stipulated isolation and quarantine guidance
Scaling up the manufacture and rolling out of vaccines vaccines as quickly and widely as possible are critical ways of protecting people before they are exposed to the virus and the risk of new variants. This includes ensuring equitable access to COVID-19 vaccines to address the evolving pandemic. Priority should be given to vaccinating high-risk groups everywhere to maximize global protection against new variants and minimize the risk of transmission. As more people get vaccinated, virus circulation is expected to decrease, which will consequently lead to fewer mutations.
What impact do the new variants of the COVID-19 virus have on vaccines?
The COVID-19 vaccines currently in approved or in development prompt a broad immune response involving a range of antibodies and cells; and are expected to provide at least some protection against new virus variants. Data continues to be collected and analysed on new variants of the COVID-19 virus. The World Health Organisation (WHO) has established a SARS-CoV-2 Risk Monitoring and Evaluation Framework to identify, monitor and assess variants of concern; and is working with researchers, health officials and scientists to understand how these variants affect the virus’s behaviour, including their impact on the effectiveness of vaccines.
If it is found that any of these vaccines prove to be less effective against one or more variants, manufacturers may have to adjust to the evolution of the COVID-19 virus (e.g. vaccines may need to incorporate more than one strain when in development, booster shots may be required, and other vaccine changes may be needed). Additional trials of sufficient scale and diversity will be needed to allow any changes in efficacy to be assessed. Studies of the impact of vaccines as they are deployed are also warranted in order to understand their impact.
Why is it important to get vaccinated even if there are new variants of the virus?
Vaccines are a critical tool in the battle against COVID-19 and concerns about new variants should not deter us from being vaccinated.