COVID-19 vaccination campaigns started less than two months ago, and more than 134 million doses have already been administered, according to Bloomberg’s vaccine tracker. That’s more doses than the number of confirmed worldwide COVID-19 infections so far, but not enough to alter the course of the pandemic. The world is far from reaching herd immunity, which could put a stop to the pandemic, with the same tracker estimating that it would take some 6.6 years to vaccinate 75% of the planet’s population at the current rate of nearly 4.75 million doses per day. That’s a deeply flawed estimate, however, as it doesn’t account for upcoming ramps in production and additional vaccines that will be authorized in the coming months and years.
That said, there’s a new problem that worries researchers: mutations. At least one of the recently discovered coronavirus mutants might reduce the efficacy of current vaccine candidates, and this could lead to additional delays in reaching herd immunity. But the vaccines still work against some known mutations, including the UK variant that’s dominant in Great Britain and making its way around the US and other regions. The good news is that new research indicates the Moderna vaccine is effective against the UK strain and a mutation seen in different variants.
Researchers from the Emory University School of Medicine in Atlanta, the University of Texas Medical Branch, and the COVID-19 Neutralization Study Group tested the vaccine against the UK variant of the virus, publishing their results online in a study that hasn’t been peer-reviewed (via News Medical).
The team looked at three categories of neutralizing antibodies to measure the Moderna drug’s efficacy against the B.1.1.7 virus. The B.1.1.7 strain of SARS-CoV-2 is a collection of genetic changes, not just a single mutation. Some of them occurred at the spike protein level, which explains why scientists are retesting the efficacy of their vaccines. The researchers took plasma from 20 patients with acute infections, 20 patients who recovered from COVID-19, and 14 healthy individuals who were vaccinated. All these blood samples contained different levels of neutralizing antibodies that should bind to the novel coronavirus’s spike protein.
The 20 people with an acute infection developed COVID-19 symptoms between 8 and 24 days before samples were collected. The recovered patients had COVID-19 between 30 and 90 days before the test. The immunized patients received both Moderna shots, which are given 28 days apart, and the sera samples were collected 14 days after the second jab.
The scientists tested all these samples against several coronavirus strains, including an early version of the virus obtained in Washington (WA1), a D614G variant isolated in Georgia in March 2020 (EHC-083E), and a B.1.1.7 variant from California. Finally, the researchers also tested the samples against a recombinant SARS-CoV-2 virus containing a single point mutation at the spike protein in position 501 (N501Y).
The authors found that all types of neutralizing antibodies, whether they were developed in response to direct infection or after vaccination, worked just as well. The team did not observe any reduction in levels of neutralizing antibodies against any of the variants, an indication that the Moderna drug works. “These results show that neutralizing antibody titers following natural infection or vaccination are effective against the UK variant (B.1.1.7) and viral strains containing single point mutations at positions 501 and 614 within the spike protein,” the team said.
These findings indicate that the vaccine can protect against severe COVID-19 and death after infection with B.1.1.7 and other strains containing the 501 mutation. The South African mutation also features the N501Y change. A different study also showed that the Pfizer/BioNTech vaccine, an mRNA drug like Moderna’s candidate, works against the B.1.1.7 and N501Y mutations.
Also important is the implication that people who survived an infection from the novel coronavirus at some point before the UK mutation was discovered should be protected against the UK strain.
However, the South African mutation also contains multiple genetic changes. The new study did not test the Moderna vaccine against the full B.1.351 strain from South Africa. Existing experiments proved that COVID-19 survivors could be reinfected with B.1.351. South African authorities halted the Oxford vaccine rollout in the region, following disappointing results in recent tests. Separately, Moderna announced a few days ago that it’s working on a booster shot for its vaccine that could help with efficacy against newer mutations, including South African mutation…Read more>>