COVID News Brief: Booster Shots Expand as Omicron Looms

Man Getting Vaccinated

At this time, the best way to fight COVID-19 and its variants is through vaccination. And the best way to battle the dominant Delta strain is booster vaccines. So far, initial data suggests boosters are likely to help battle Omicron as well. For that and more COVID-19 news, read on.

FDA Expands Pfizer-BioNTech Vaccine Booster Eligibility to 16- & 17-Year-Olds

The U.S. Food and Drug Administration (FDA) modified the emergency use authorization (EUA) for the Pfizer-BioNTech vaccine, granting the use of a single, third booster shot for people 16 and 17 years of age. It is to be given at least six months after receiving the primary vaccination.

“Vaccination and getting a booster when eligible, along with other preventive measures like masking and avoiding large crowds and poorly ventilated spaces, remain our most effective methods for fighting COVID-19,” said Acting FDA Commissioner Janet Woodcock.

WHO Advisory Group Supports J&J Vaccine as a Booster

The World Health Organization (WHO)’s Strategic Advisory Group of Experts on Immunization (SAGE) made an interim recommendation that the Johnson & Johnson single-shot COVID-19 vaccine could be used as a booster shot in people 18 years and older. The booster was recommended two to six months after the primary vaccination. The advisory group recommended it be used as a booster for people who received the J&J vaccine originally. The WHO also supports so-called mix-and-match boosting, with the J&J vaccine as a booster for people 18 and older who received other COVID-19 vaccines as their primary regimen.

Vaccine Makers Unsure if Omicron-Focused Vaccines Worthwhile

Just as no vaccine makers developed and distributed a modified COVID-19 vaccine targeting the Delta variant, none have done so for the new variant, Omicron, either. Instead, the approach appears to be pushing for booster shots of the original vaccines, which in laboratory tests appears to be effective against Omicron and other variants. 

One technical reason vaccine makers are hesitant is what immunologists call “original antigenic sin.” A less biblical term is “imprinting,” and was first recognized in older people and the flu vaccines. Different strains of the flu dominate in different years and each one evolves quickly. As a result, drug companies make an educated guess each year on the right version of the 20 known flu viruses to include in the annual vaccine. 

Imprinting is that no matter which vaccine design, individuals create the most potent and durable antibodies against the flu strains they were first exposed to as children. So immunologists and vaccine makers have concerns that this could happen with COVID-19 vaccines — that although it’s relatively easy and quick to modify a vaccine, particularly the mRNA vaccines by Pfizer-BioNTech and Moderna, it’s not as clear if immune systems could adapt well to the new instructions in the modified vaccines. It’s possible that the immune system would primarily continue to create copies of the antibodies they were originally “programmed” to produce after their first infection or vaccination.

So far, the data suggests that won’t be a problem with SARS-CoV-2.

McMaster University Starts Clinical Trial for Inhaled COVID-19 Vaccines

McMaster University researchers are initiating clinical trials for two inhaled COVID-19 vaccines that are specifically designed to fight variants of concern (VOC). The vaccines include next-generation aerosol technology to target the lungs and upper airways.

“We’ve developed a COVID vaccine that contains three of the proteins of COVID-19,” said Fiona Small, a microbiologist at McMaster. “The novel part of our vaccine is not only the part around the development of the vaccine cells, but the administration of it. That’s probably the most exciting part. Instead of giving the vaccine by intramuscular injection, we’re giving that by an aerosol inhalation directly into the lungs using a small jet nebulizer that is very comfortable to administer.”

The Phase I trial will evaluate the vaccine's safety in people who previously received two doses of either the Pfizer-BioNTech or Moderna vaccines.

German and UK Researchers Successfully Tested New Approach to Treating COVID-19

Researchers at the University of Frankfurt in Germany and the University of Kent in the UK conducted preclinical testing on compounds that inhibit a newly discovered metabolic pathway in SARS-CoV-2, the virus that causes COVID-19. The compound is benfo-oxythiamine and inhibits a pathway called pentose-phosphate. The pentose-phosphate pathway is key for the propagation of the COVID-19 virus in human cells. The general concept is that although you might become infected with the virus, the drug would prevent the virus from replicating.

Ribose-5-phosphate is a building block needed to form new RNA or DNA. SARS-CoV-2 modifies the sugar metabolism of the infected cell to efficiently manufacture ribose-5-phosphate. An infected cell can only create new viruses if ribose-5-phosphate is present. So by inhibiting that building block’s production, the viruses can’t replicate.

One of the potential positive aspects of this approach is that it is not dependent upon gene sequences and mutations of the virus. It is, instead, directed against all types of viruses, including non-coronaviruses, potentially.

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