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Coronavirus

CDC bolsters surveillance of highly contagious Indian COVID-19 variant

Published: Updated:

Federal Health officials are ramping up their surveillance of the highly transmissible COVID-19 variant first identified in India as experts warn that under-vaccinated areas in the US could become hot spots for the mutation.

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While US cases attributed to the B.1.617 variant currently sit below 1 percent, the growth rate remains unclear due to the small sample size. Meanwhile, one science group said the strain could be as much as 50 percent more transmissible than B.1.1.7, the variant that emerged from the UK That mutation was first seen in the US in late December and is now dominant nationally.

A just-released UK study found the Pfizer.-BioNTech vaccine was “highly effective against a form of the B.1.617 variant two weeks after the second dose, affirming preliminary data from Phase 3 clinical trials. Still, the mutation has arrived in the US at a time when anti-pandemic measures are loosening and around 60 percent of the population isn’t yet fully vaccinated.

“From everything I can tell the vaccines are highly effective against this variant,” said Samuel Scarpino, a co-founder of Global.health, an organization that tracks COVID-19 cases and variants internationally. “But there are some states in the US with quite low vaccination coverage putting them at risk for potential outbreaks.”

The B.1.617 variant that has devastated India was first detected in the US between late February and late March of this year. On May 4, the US Centers for Disease Control and Prevention designated B.1.617 as a variant of interest. It is now studying whether to escalate its standing to a variant of concern, said Jade Fulce, a CDC spokesperson.

Family members of Vijay Raju, who died due to the coronavirus disease (COVID-19), mourn before his cremation at a crematorium ground in Giddenahalli village on the outskirts of Bengaluru, India, May 13, 2021. (File Photo: Reuters)
Family members of Vijay Raju, who died due to the coronavirus disease (COVID-19), mourn before his cremation at a crematorium ground in Giddenahalli village on the outskirts of Bengaluru, India, May 13, 2021. (File Photo: Reuters)

Currently, the CDC has classified eight variants of interest, three of which are forms of the B.1.617 strain, according to the CDC website. The agency says these variants are “predicted to affect transmission, diagnostics, therapeutics, or immune escape, but still have limited prevalence or expansion in the US or in other countries.”

Variants of Concern

There are five variants of concern listed by the CDC. This category covers those that show “evidence of impact on diagnostics, treatments or vaccines along with increased transmissibility and/or disease severity”.

Local health agencies are urged to report these cases to the CDC, who will also report them to the World Health Organization (WHO). The designation will also spur efforts to control the variant’s spread and, potentially, development of new diagnostics or the modification of vaccines or treatments.

So far, according to the CDC’s Fulce, there is “insufficient data to evaluate with a high degree of confidence whether these lineages are variants of concern.

Agency efforts to determine variant classification include reviews of the latest case percentages, as well as laboratory, epidemiological and clinical research data, according to Jasmine Reed, another CDC spokesperson. The CDC also is in touch with global partners, including the WHO, to share data and coordinate genomic surveillance and characterization of variants, Reed said.

UK Study

The recently-released UK study by Public Health England found both the Pfizer vaccine, authorized for use in the US on an emergency basis, and the AstraZeneca Plc shot, which isn’t yet available in the US, to be “highly effective against the B.1.617.2 form of the variant first detected in India.

The study was conducted from April 5 to May 16. Pfizer-BioNTech shot was 88 percent effective against the B.1.617.2 variant two weeks after the second dose. Two doses of the AstraZeneca vaccine were 60 percent effective.

“We expect the vaccines to be even more effective at preventing hospitalization and death,” said Mary Ramsay, head of immunization at Public Health England. “So it is vital to get both doses to gain maximum protection against all existing and emerging variants.”

Still, some health experts are questioning if the CDC is doing enough as experts warn that with states opening up, and anti-pandemic measures loosening, under-vaccinated pockets of the US could be at risk of B.1.617 outbreaks.

US vaccine roll-out efforts vary state by state. New Mexico, Maine and New Jersey have administered enough doses to cover more than half of their population. Other regions, however, are lagging. Idaho, Wyoming and Louisiana have administered enough doses for just under 35 percent of their population, while Mississippi and Alabama have administered enough for only 30 percent.

A health worker prepares an injection of the Pfizer-BioNTech vaccine against the coronavirus at a vaccination centre, set up at the Dubai International Financial Center in the Gulf emirate of Dubai, on February 3, 2021. (AP)
A health worker prepares an injection of the Pfizer-BioNTech vaccine against the coronavirus at a vaccination centre, set up at the Dubai International Financial Center in the Gulf emirate of Dubai, on February 3, 2021. (AP)

“I think the CDC should be doing more in terms of communicating the risks of this variant, and that should translate into states taking precautions more seriously than we’re currently doing,” Global.health’s Scarpino said.

Spike Protein

Scientists pay most attention to mutations in the gene that encodes the SARS-CoV-2 spike protein, which plays a key role in viral entry into cells. Targeted by vaccines, this protein influences immunity and vaccine efficacy. B.1.617 is among several variants that carry multiple mutations affecting the spike protein.

The WHO earlier this month declared B.1.617 a variant of global concern based on early evidence suggesting it is highly contagious and carries at least some propensity to evade antibodies, including bamlanivimab, a monoclonal antibody therapy developed by AbCellera Biologics Inc. and Eli Lilly & Co. The mutation was detected in 44 countries as of mid-May amid a dramatic spike in cases.

It is “highly likely that this variant is more transmissible than B.1.1.7, the variant first detected in the UK, and possibly as much as 50 percent more transmissible,” the UK’s Scientific Advisory Group for Emergencies said on May 13.

UK Sampling

The UK is sampling around 50 percent to 60 percent of all positive COVID-19 samples, said Moritz Kraemer an epidemiologist at the University of Oxford, which provides crucial detail of the distribution of the B.1.617 variant. Rigorous sequencing allowed authorities to identify 2,323 cases of the mutation on Monday.

In Bolton and Blackburn, towns in northwestern England, cases of the India variant doubled in just a week. Most people with the India variant in areas around Bolton had not been vaccinated.

Almost 40 percent of Americans have been fully vaccinated, and roughly half of the US population have received at least one shot. But as more people are interacting and socializing there are more possibilities for transmission, Kraemer said during a phone interview.

“For any variant, if there are lots of infectious people coming into the country at a particular locality, if there are a population of people who are unvaccinated it’s fair to say that there’s a high risk that those areas could become hot spots,” he said.

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