Chinese vaccine 65.9% effective in Chile (n=10,200,000)
Effectiveness of an Inactivated SARS-CoV-2 Vaccine in Chile
We used a prospective national cohort, including participants 16 years of age or older who were affiliated with the public national health care system, to assess the effectiveness of the inactivated SARS-CoV-2 vaccine. the cohort included approximately 10.2 million persons. Among persons who were fully immunized, the adjusted vaccine effectiveness was 65.9% (95% confidence interval [CI], 65.2 to 66.6) for the prevention of Covid-19 and 87.5% (95% CI, 86.7 to 88.2) for the prevention of hospitalization, 90.3% (95% CI, 89.1 to 91.4) for the prevention of ICU admission, and 86.3% (95% CI, 84.5 to 87.9) for the prevention of Covid-19–related death. Our results suggest that the inactivated SARS-CoV-2 vaccine effectively prevented Covid-19, including severe disease and death, a finding that is consistent with results of phase 2 trials of the vaccine.
Is one vaccine dose enough if you’ve had COVID? What the science says
[Nature news feature.] Studies show that people with previous exposure to SARS-CoV-2 tend to mount powerful immune responses to single shots, and gain little added benefit from another injection. What’s more, for people with immunity gained through infection, one dose typically boosts antibody numbers to levels that are equal to, or often greater than, those found in individuals who have not been infected and have received double doses. France, Germany and Italy, among other countries, now advise only one dose of vaccine for people with a healthy immune system and a confirmed previous diagnosis.
COVID-19 mRNA vaccine induced antibody responses against three SARS-CoV-2 variants
Here we show, that after the second dose, the sera of [Pfizer] BNT162b2-vaccinated health care workers (n = 180) effectively neutralize the SARS-CoV-2 variant with the D614G substitution and the B.1.1.7 variant, whereas the neutralization of the B.1.351 variant is five-fold reduced. Despite the reduction, 92% of the seronegative vaccinees have a neutralization titre of >20 for the B.1.351 variant indicating some protection. The vaccinees’ neutralization titres exceeded those of recovered non-hospitalized COVID-19 patients. Our work provides evidence that the second dose of the BNT162b2 vaccine induces cross-neutralization of at least some of the circulating SARS-CoV-2 variants.
COVID vaccines and breastfeeding: what the data say
[Nature news feature.] The vaccines do not pass through breast milk, but antibodies do — providing hope that breastfed babies might have some level of protection.
Why Uruguay lost control of COVID
[Nature news feature.] Complacency and a coronavirus variant help to explain why the country, once a pandemic success story, couldn’t withstand the surge now rocking South America.