Read more about these studies in Nature’s continuously updated selection of the must-read papers and preprints.
Vaccinating adults protects unvaccinated kids too
Vaccinating many people against SARS-CoV-2 could stall infection rates, even among unvaccinated children in the same community. Researchers looked at 223 Israeli communities in which older people had been widely vaccinated with the Pfizer–BioNTech vaccine. The infection risk among children under 16 dropped proportionally to the percentage of adults who had been vaccinated.
(Reference: medRxiv preprint — not peer reviewed)
Variants spur multi-talented antibody response
Antibodies from people infected with the 501Y.V2 coronavirus variant (also called B.1.351), first identified in South Africa, are also effective against previously circulating variants when tested in a laboratory dish. This implies that updated vaccines against 501Y.V2 could also protect against earlier coronavirus variants.
(Reference: Nature paper)
Real-world evidence that vaccines stop infection
A full vaccination reduces risk of SARS-CoV-2 infection by roughly 90%, and a single dose is 80% effective, according to a study of US nurses, firefighters and other front-line workers. Study participants received either the Moderna or Pfizer–BioNTech vaccines. The researchers caution that because very few participants became infected after vaccination, it’s difficult to state the vaccines’ effectiveness against infection with high precision. Clinical trials already showed that the two mRNA-based vaccines are highly effective at protecting people from getting COVID-19, the disease caused by SARS-CoV-2.
(Reference: Morbidity and Mortality Weekly Report paper)
Antibodies last for months — if you have them
A study of more than 9,500 people in Wuhan, China — once the epicentre of COVID-19 — found that only 7% of the population had been infected with SARS-CoV-2, of whom more than 80% had had no symptoms. Around 40% of the infected people produced neutralizing antibodies that could be detected for the entire 9-month study period. The researchers conclude that most people in Wuhan are still susceptible to SARS-CoV-2 infection, and that a mass-vaccination campaign is needed to achieve herd immunity.
(Reference: The Lancet paper)
Older people are at higher risk of getting COVID twice
Natural infection with SARS-CoV-2 protects against reinfection in most people — but this protection is significantly weaker in those aged 65 years or older. Researchers analysed millions of coronavirus test results in Denmark and found that, at about 6 months after initial infection, protection against repeat infection was approximately 80%, with no significant difference in reinfection rates between men and women. But this protection was reduced to 47% for those aged 65 years or older.
(Reference: The Lancet paper)
Get more of Nature’s continuously updated selection of the must-read papers and preprints on COVID-19.