Published: Sun, January 31, 2021
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COVID-19 vaccines: Efficacy varies in different scenarios

COVID-19 vaccines: Efficacy varies in different scenarios

A global study of almost 44,000 found that the COVID-19 vaccine made by Johnson & Johnson is 66% effective in preventing moderate to severe disease.

The company says it plans to apply to the Food and Drug Administration for emergency use authorization to distribute the vaccine.

South Africa will receive another 20 million doses of the COVID-19 vaccine manufactured by Pfizer, according to a report by The Sunday Times.

The overall effectiveness rate for preventing moderate to severe illness was 72% in the USA and 66% across all countries studied, the pharmaceutical giant said.

Benefits include that it only requires one dose - as opposed to Moderna and Pfizer's two-dose inoculations - and that it can be stored in a regular refrigerator.

Their efficacy rates, which exceeded 90 percent in clinical trials, were reported prior to growing concerns over what appears to be more contagious variants initially detected in Britain and South Africa.

Barouch said there are now a wide variety of new variants circulating, including in Brazil, South Africa and even the USA, that are substantially resistant to vaccine-induced antibodies.

"These topline results with a single-shot Covid-19 vaccine candidate represent a promising moment", said Paul Stoffels, Vice Chairman of the Executive Committee and Chief Scientific Officer, Johnson & Johnson.


Another highly transmissible variant first discovered in the United Kingdom and now in more than half of U.S. states has been less able to evade vaccine efficacy than its South African counterpart. Its high efficacy in preventing severe disease will help prevent health services from becoming overwhelmed by serious cases.

"What we are learning is there is different efficacy in different parts of the world", Stoffels said in a telephone interview.

J&J has said it plans to deliver 1 billion doses in 2021 and will produce the vaccine in the United States, Europe, South Africa and India.

Novavax said it began working on new vaccines against emerging strains in early January and expects to select ideal candidates in the coming days, then begin clinical testing in the second quarter of the year. "We look forward to continuing to work with our partners, collaborators, investigators and regulators around the world to make the vaccine available as quickly as possible".

The COVID-19 vaccines purchased by South Africa will comprise two doses, administered one to three weeks apart.

But nobody needed hospital treatment or died from coronavirus after the vaccine took effect in the global trial.

US trial results for the vaccine from AstraZeneca Plc and Oxford University are expected in early February, opening up the possibility of a fourth vaccine option.

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