In this week's roundup, the latest scientific research on the coronavirus and efforts to find treatments and vaccines suggest that new COVID-19 vaccines could be manufactured like flu shots, intranasal boosters use virus spikes to enhance immunity and lung transplants can help the sickest coronavirus survivors.
New jab could be like flu shots
A COVID-19 vaccine that can be produced locally in low- and middle-income countries is yielding promising results in early clinical trials, researchers say.
The NDV-HXP-S vaccine, developed at Icahn School of Medicine at Mount Sinai in New York City, uses an engineered version of the harmless Newcastle disease virus studded with coronavirus spike proteins to teach the immune system to recognize and attack the virus that causes COVID-19.
Using blood samples from trial participants, researchers found that NDV-HXP-S induces proportionally more antibodies that can neutralize the virus and fewer non-neutralizing antibodies than the current messenger RNA (mRNA) vaccines from Moderna or Pfizer-BioNTech, they reported Friday on medRxiv ahead of peer review.
"The NDV-HXP-S vaccine induced neutralizing antibody responses against wild type (the original) SARS-CoV-2 that matched what we see after mRNA vaccination, but the proportion of neutralizing antibodies in the response was higher for NDV-HXP-S," said Mount Sinai's Florian Krammer.
The vaccine can be manufactured like flu vaccines at low cost in chicken eggs at influenza vaccine manufacturing plants around the world, his team said. Early clinical trials with a live version are underway in Mexico and the United States, while an inactivated version is being tested in Vietnam, Thailand and Brazil, a spokesperson said.
Midstage trials of the inactivated vaccine have also been completed and pivotal randomized trials are being planned.
Intranasal boosters and immunity
Once the body has been "primed" by mRNA vaccines to recognize and attack the coronavirus, a booster containing purified versions of the virus' spike protein that could be given intranasally would have many advantages, researchers believe.
Their "Prime and Spike" strategy employs a booster vaccine currently being tested in animals.
In mice with waning immunity after two doses of the Pfizer-BioNTech shot, the purified spike protein vaccine strongly boosted first- and second-line immune responses to the virus in the nose, lungs and blood, and protected against lethal doses of the virus, researchers reported Wednesday on bioRxiv ahead of peer review.
Furthermore, the mice had lower-than-expected viral loads, which would likely reduce transmission. In mice whose immune systems had not been "primed" with the mRNA vaccine, the spike protein vaccine had no effect, however, because it takes advantage of the body's adaptive immunity, it builds upon what the immune system has learned from the mRNA vaccine.
"This strategy is likely to confer long-lasting and cross-reactive memory that can be quickly restimulated to prevent viral spread," study leader Akiko Iwasaki of Yale University explained on Twitter.
"The intranasal spike protein booster will also be much easier to administer (via nasal spray) ... and is much more likely to be accepted by people who are hesitant of mRNA or those with needle phobia," Iwasaki said.
Lung transplants can help the sickest
People who need lung transplants as a result of COVID-19 do just as well afterward as those who get new lungs for other reasons, early data suggest.
The findings are reassuring, researchers say, because poor outcomes might rule out these patients' transplant eligibility even if their lungs were completely destroyed, given the shortage of available organs.
From August 2020 through September 2021, 3,039 lung transplants were performed in the U.S., 7% of which were done in COVID-19 survivors whose lungs had been irreparably damaged by the virus, researchers reported on Wednesday in The New England Journal of Medicine.
Overall, 197 COVID-19 survivors received two lungs and 17 received single lungs. Some patients also required new hearts or kidneys. The survival rate at three months post-transplant was 95.6%, which "approached that among patients who underwent lung transplantation for reasons other than COVID-19," the researchers said.
It is unclear how well these patients will do in the long term, but it appears "that lung transplantation may be an acceptable treatment for selected patients with irreversible respiratory failure due to COVID-19," they concluded.