Challenges and Opportunities With Coronavirus Variants

SARS-CoV-2 is like other RNA viruses changing through mutation with new variants occurring
man at chalkboard explaining mutations
(Coronavirus Today)

When new virus variants become more common, they do so because of some selective advantage to the virus, stated a new editorial published by JAMA.

Among the numerous SARS-CoV-2 variants that have been detected, only a very small proportion are of public health concern because they are more transmissible, cause more severe illness, or can elude the immune response that develops following infection and possibly from vaccination, continued this editorial, which is edited and excerpted below.

‘In the recent months, 3 specific viral lineages reflecting variants of concern have emerged and merit close monitoring: B.1.1.7, B.1.351, and P.1.’

The B.1.1.7 lineage (known as 20I/501Y.V1 or variant of concern [VOC] 202012/01) was first detected in the UK in December 2020 with likely emergence during the preceding September; this variant has now been identified in at least 80 countries. 

The first identified US case of the B.1.1.7 variant was detected in Colorado in late December 2020. Since then, B.1.1.7 has been detected in at least 33 US states. 

Another VOC, the B.1.351 lineage (known as 20H/501Y.V2) was first identified in the Republic of South Africa in December 2020 with likely emergence before October; this variant has been identified in at least 41 countries including the US, where it was first detected in South Carolina and Maryland in late January 2021.

The SARS-CoV-2 P.1 lineage (known as 20J/501Y.V3) was identified in December 2020 in travelers from Brazil, with the first case in the US detected in Minnesota in January 2021.

Preliminary data from the UK suggest that the B.1.1.7 variant is more transmissible than previous variants of SARS-CoV-2 and preliminary data suggest the possibility of increased severity of disease with infection.

Some data also suggest that people infected with an earlier form of circulating SARS-CoV-2 may have reduced protection from reinfection with the B.1.351 variant. 

This observation and a report of an approximately 6-fold reduction in the neutralization of B.1.351 variants by sera from vaccinated individuals with a vaccine designed against wild-type virus suggest that currently employed vaccines might be less effective at preventing infection due to this variant.

It should be noted that this type of assessment, neutralizing antibodies from vaccinated or previously infected individuals, does not assess other types of potential immunity, such as memory T- and B-cell activity.

Modeling data have illustrated how a more contagious variant, such as B.1.1.7, has the potential to exacerbate the trajectory of the US pandemic and to reverse the present downward trend in new infections, and further delay control of the pandemic.

A recent report from Minnesota in the U.S. CDC’s Morbidity and Mortality Weekly Report (MMWR) on B.1.1.7 variant cases highlighted the risk of domestic and international travel.

By February 3, 2021, genomic sequencing of circulating viruses from one commercial laboratory suggests that the nationwide prevalence of the B.1.1.7 variant in the US is now approaching 1%, with prevalence in some states exceeding 2%.

There are also signs of concerning increases in cases attributed to the B.1.351 variant in some countries. 

A recent CDC MMWR report shows the substantial increase in the B.1.351 variant that occurred in Zambia, going from none detected by genomic sequencing of a subset of samples from March to early December to 22 of 23 samples (96%) sequenced from a 1-week period in mid-December, corresponding with a more than 16-fold increase in COVID-19 incidence in Zambia from early December to early January 2021.

The possibility of a similar experience in the US is a real threat. 

However, such an outcome is not inevitable; the US and other countries have the capability to prevent this outcome from occurring with a strong and immediate public health response.

To ensure a proactive rather than reactive response, the Department of Health and Human Services (HHS) established a SARS-CoV-2 Interagency Group (SIG) to improve coordination among CDC, the National Institutes of Health (NIH), the Food and Drug Administration (FDA), the Biomedical Advanced Research and Development Authority (BARDA), the US Department of Agriculture (USDA), and the Department of Defense (DoD). 

The SIG focuses on the rapid characterization of the emerging VOC and actively monitors their potential influence on critical SARS-CoV-2 countermeasures including diagnostics, therapeutics, and vaccines.

To ensure that diagnostic testing continues to reliably identify infections including those caused by VOC, FDA and CDC are working together with the industry to evaluate tests already approved for SARS-CoV-2 detection under Emergency Use Authorization. 

To address the risk of reinfection and ensure vaccine effectiveness, NIH, CDC, and DoD are conducting in vitro neutralization assays to assess the neutralizing activity of human convalescent and postvaccination sera, respectively, against VOC. 

Similarly, NIH and DoD are assessing the effects of the emerging variants on the efficacy of certain therapeutics by conducting in vitro and in vivo neutralization assays with an authorized monoclonal antibody and polyclonal antibody products.

The public health response within the US needs to address not only SARS-CoV-2 variants from other countries, but also be vigilant for the evolution of domestic VOC given the high levels of transmission in much of the nation. 

A multipronged public health response is needed. A concerted and well-coordinated public health effort, together with rapid and widespread uptake of effective vaccines, is essential to remain ahead of the inevitable evolution of variants that could dangerously accelerate the trajectory of the pandemic, concluded this edited editorial written by Rochelle P. Walensky, M.D., MPH; Henry T. Walke, M.D., MPH; Anthony S. Fauci, M.D.

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