People on six continents already are getting jabs in the arm as the race for a COVID-19 vaccine enters a defining summer, with even bigger studies poised to prove if any shot really works — and maybe offer a reality check.
Already British and Chinese researchers are chasing the coronavirus beyond their borders, testing potential vaccines in Brazil and the United Arab Emirates because there are too few new infections at home to get clear answers.
Vaccines by Sinovac Biotech and SinoPharm use that old-fashioned technology, which requires high-security labs to produce but is dependable, the way polio shots and some flu vaccines are made.
Only if the virus starts spreading through a community several weeks after volunteers receive either a vaccine or a dummy shot — time enough for the immune system to rev up — do scientists have the best chance at comparing which group had more illness.
In addition to the planned U.S.-run study, Brazil last week began a last-stage test of the Oxford shot in 5,000 health workers, the first experimental COVID-19 vaccinations in South America.
