Composition of Covid 19 vaccine
Answers
Explanation:
Why Are 2 Vaccine Doses Needed? When the vaccines were first tested, a relatively weak immune reaction was found within a few weeks after people received the first dose of vaccine, followed by a strong reaction when a second dose was given.There is no evidence that the Bacille Calmette-Guérin vaccine (BCG) protects people against infection with COVID-19 virus. Two clinical trials addressing this question are underway, and WHO will evaluate the evidence when it is available.The Pfizer BioNTech vaccine BNT162b2 is likely to be effective against the B1.1.7 variant of SARS-CoV-2, even though its efficacy is modestly affected, say scientists at the University of Cambridge.The Oxford and AstraZeneca researchers also found that a single dose of the vaccine was 76 percent effective at preventing Covid-19. The data measured the three months after the first shot was given, not including an initial three-week period needed for protection to take effect.So far, none of the vaccine trials have reported any serious safety concerns. Trials for the first two vaccines — from Pfizer and Moderna — have had fully independent safety monitoring boards, and safety data are continuously reviewed by the FDA and expert panels.
Answer:
Answer in the attachment
Hope you got your answer
Keep Learning
