Trial launched for vaccine against one of scariest coronavirus variants

Researchers have distributed the first jabs of a modified version of Moderna’s COVID-19 vaccine, aimed at tackling one of the most worrying coronavirus variants – variant B.1.351, first identified in South Africa .

The jabs are part of an early trial of the modified vaccine, which is being run by the NIH’s National Institute of Allergy and Infectious Diseases (NIAID). The agency aims to enroll around 210 healthy adults in the trial by the end of April.

“The B.1.351 variant of SARS-CoV-2, first identified in the Republic of South Africa, has been detected in at least nine states in the United States,” said Anthony Fauci, director of NIAID, in a statement. “Preliminary data shows that the COVID-19 vaccines currently available in the United States are expected to provide an adequate level of protection against variants of SARS-CoV-2. However, out of caution, NIAID continued its partnership with Moderna to evaluate this variant of the vaccine candidate in the event of a need for an updated vaccine.

Data so far on variant B.1.351 (aka 501Y.V2) suggests that it may be around 50% more transmissible than earlier versions. It also appears to elude immune responses from past infections and current vaccines. Laboratory experiments have shown that it takes about six times the amount of antibodies recovered from COVID-19 patients to neutralize the variant, compared to the amount needed to neutralize an earlier version of the virus. The variant also appeared to reverse the Johnson & Johnson vaccine; the vaccine appeared to be 72% effective in preventing symptomatic COVID-19 in the United States, but was only 64% effective in South Africa, while the B.1.351 variant was widely distributed.

The worrisome abilities of B.1.351 probably stem from key mutations in its spike protein, the protruding protein that protrudes from the outside of SARS-CoV-2 viral particles. The virus uses the spike protein to bind and enter human cells. Some of the strongest antibodies against the virus bind at the peak, where they can physically prevent the virus from binding to cells.

Tweaks and tests

The original Moderna vaccine works by supplying human cells with the genetic code for the SARS-CoV-2 peak in the form of mRNA. Once delivered, our cells read the code and make their own spike protein, which is used to drive immune responses to spot and destroy any SARS-CoV-2 invaders. For the modified version of the vaccine, Moderna researchers simply incorporated key mutations of the B.1.351 variant spike protein into the mRNA code used in the vaccine.

As Fauci mentioned in his statement, it’s unclear how necessary these variant-specific vaccines will be, given that current vaccines offer some protection. However, with SARS-CoV-2 still widely circulating in the United States and around the world, there are many opportunities for the virus to continue to mutate. With each new infection, there is a greater chance that mutations and new variants will appear, which in turn increases the chances that variant-specific vaccines will be a fixture in our future.

To understand how the variants might fit into current vaccine use, the new NIH trial is testing 10 different vaccine regimens. About 60 of the 210 people the institute aims to recruit will be people from the initial Moderna vaccine trial, who were first immune to COVID-19 last year. Some of these people will receive a single booster vaccine with only the variant-specific vaccine, while others will receive a booster containing a mixture of the original vaccine and the variant-specific vaccine.

The remaining 150 people in the trial will be those who have not yet received a COVID-19 vaccine. Two groups of 15 will receive three injections at varying doses, 28 days apart: two doses of the original vaccine, then a variant-specific booster. Two groups of 20 will receive just two shots at varying dosages of the variant-specific booster. Two groups of 20 will receive two injections at varying dosages: one dose of the original vaccine and then a variant specific booster. Finally, two groups of 20 will receive two injections, each containing mixtures of the original vaccine and variant-specific vaccine at varying dosages.

Researchers will then monitor participants for safety concerns, side effects, and immune responses against the SARS-CoV-2 viruses.