巴西小城在试验半支AZ疫苗。
1 hr 42 min ago
Small town in Brazil to give only half dose of AstraZeneca vaccine as part of trial
From journalists Rodrigo Pedroso and Tatiana Arias
Residents of Viana, a small town in southeastern Brazil, are taking part in a new coronavirus study in which medical researchers are trying to vaccinate all of the town's adult population ages 18 to 49 against Covid-19, but with only half the typical dose of AstraZeneca's vaccine.
In the study, most of Viana’s adult population will be given two half-doses of the AstraZeneca vaccine three months apart – the usual timespan in which AstraZeneca doses are administered in Brazil. The researchers from Brazil’s Fiocruz Foundation are examining whether a half-dose can provide enough protection against the virus, and then compare its efficacy with the full dosage.
“AstraZeneca studied some individuals and found antibody levels similar to the standard dose in all age groups. Our hypothesis is that half a dose is enough to generate protection against Covid-19. We expect at least 60% of effectiveness,” project head Dr. Valeria Valim, also professor at Espirito Santo Federal University, said during a press conference on June 4.
The study aims to vaccinate 35,000 people, around 85% of Viana's population.
The town was chosen for its closeness to the metropolitan region of Vitoria, Espirito Santo state’s capital, which is a Covid-19 hotspot.
The first round of vaccinations is expected to take two days, to be administered on Sunday, June 13 and Monday, June 14, and will be done using AstraZeneca doses donated by the Brazilian health ministry.
