Delta variant doubles risk of hospitalization; Novavax vaccine highly effective in large trial

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FILE PHOTO: An illustration, created at the Centers for Disease Control and Prevention (CDC), depicts the 2019 Novel Coronavirus

By Nancy Lapid

(Reuters) - The following is a roundup of some of the latest scientific studies on the novel coronavirus and efforts to find treatments and vaccines for COVID-19, the illness caused by the virus.

Delta variant doubles risk of COVID-19 hospitalization

The delta variant of the coronavirus first identified in India may double the risk of hospitalization among COVID-19 patients, compared with the alpha variant first discovered in the UK, a study from Scotland suggests. Researchers looked at 19,543 COVID-19 cases and 377 hospitalizations among 5.4 million people, including 7,723 cases and 134 hospitalizations in patients with the delta variant, who tended to be younger and more affluent. The risk of COVID-19 hospital admission was about double with the delta variant compared to the alpha variant, with the risk particularly increased in those with five or more medical conditions known to contribute to more severe disease, the researchers reported on Monday in The Lancet. They found that two doses of the vaccines from Pfizer and BioNTech and from AstraZeneca still provide strong protection, although not as strong as the protection provided against the alpha variant. Two weeks after the second dose, the Pfizer/BioNTech vaccine was found to provide 79% protection against infection from the delta variant, compared to 92% against the alpha variant. With AstraZeneca's vaccine, there was 60% protection against delta compared with 73% for alpha. Because this was an observational study, more research is needed to confirm the findings, the research team said. (https://bit.ly/3xinW5K)

Novavax vaccine highly effective in North American trial

Novavax Inc on Monday said its COVID-19 vaccine was more than 90% effective, including against a variety of concerning coronavirus variants, in a large, late-stage clinical trial, providing another potential weapon against the disease once approved for use. In the trial involving nearly 30,000 volunteers in the United States and Mexico, the two-shot vaccine was 100% effective in preventing infection by the original version of the coronavirus, the company said. It was more than 93% effective against the predominant variants of the virus that have been of concern among scientists and public health officials. The alpha variant first identified in the UK was the predominant variant in the United States while the trial was being conducted, the company said. The vaccine was 91% effective among volunteers at high risk of severe infection and 100% effective in preventing moderate and severe cases of COVID-19. Novavax said the vaccine was generally well tolerated, with side effects similar to those seen with existing COVID-19 vaccines. The Novavax COVID-19 shot is a more conventional type of vaccine than those currently available. It contains an actual version of the virus' spike protein that cannot cause disease but can trigger the immune system directly. The company said the results put it on track to file for emergency authorization in the United States and elsewhere in the third quarter of 2021. (https://reut.rs/3iEvUlw)

Tetanus, diphtheria boosters tied to less severe COVID-19

Older individuals who have gotten a diphtheria or tetanus vaccine booster shot in the last 10 years may be at lower risk for severe COVID-19, a new study suggests. Using a large UK registry, researchers looked back at 10 years of immunization records from 103,409 participants with an average age of 71. They saw a trend toward a lower risk of a positive COVID-19 test in people who had gotten a tetanus or diphtheria booster shot during the study period, although the difference was small and might have been due to chance. There was, however, a statistically significant association between the booster shots and the odds of severe COVID-19. After accounting for age, sex, underlying respiratory diseases, and socioeconomic status, the odds of developing severe COVID-19 were 64% lower in people who had gotten a diphtheria booster and 50% lower in recipients of tetanus booster, according to a report posted on medRxiv on Saturday ahead of peer review. The study does not prove cause and effect. If there is some effect of the boosters, it might be that they protect against severe COVID-19 symptoms by stimulating the immune system, the authors suggest. "The possibility that these vaccinations may influence the severity of COVID-19 warrants follow-up investigations," they conclude. (https://bit.ly/2SBSVLg)

Open https://tmsnrt.rs/3c7R3Bl in an external browser for a Reuters graphic on vaccines in development.

(Reporting by Nancy Lapid, Carl O'Donnell and Alistair Smout; Editing by Bill Berkrot)

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