By Spy Uganda Correspondent
Tripoli: South Africa has paused its rollout of the AstraZeneca’s vaccine after researchers discovered that it did not provide significant protection against mild to moderate Covid-19 caused by the variant of the virus dominant in the country.
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The AstraZeneca vaccine was tested among about 1750 healthy adults in South Africa. Half of those in the study were randomly assigned to receive the vaccine; the other half took a placebo of saline solution. Neither group knew which was which.
Just less than two months later, South Africa entered its second wave of Covid-19 infections — this time fuelled by a novel, faster-spreading variant of the virus.
Against this new foe, AstraZeneca’s vaccine was largely powerless to prevent mild to moderate Covid-19, says Shabir Madhi, the director of the Vaccines and Infectious Diseases Analytics Research Unit at the University of the Witwatersrand University. The findings, released in a presentation on national television, have been submitted for publication in a peer-reviewed journal and are currently being processed.
Viruses mutate commonly, creating new variants. Not all variants, however, change the way the virus spreads or affects people. The variant first discovered in South Africa has been shown to spread more quickly, but there is no evidence it causes people to become sicker.
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AstraZeneca’s findings come less than two weeks after Johnson & Johnson (J&J) issued a press release stating its one-dose Covid-19 vaccine reduced the risk of moderate to serious disease by about 57% in South African participants, despite the new variant.
However, the jab performed better in the United States, reducing that same risk by 72%. Similarly, the Novavax vaccine was found to reduce HIV-negative people’s risk of mild to severe Covid-19 in South Africa by 60%. Still, it again was found to be more effective in the United Kingdom in the absence of the variant now dominating South African Covid-19 cases.
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Madhi cautions that although current vaccines were not specifically designed to address new variants, this is likely to change. United States pharmaceutical company Moderna is already studying a booster shot to improve its vaccine’s efficacy against the variant dominant in South Africa after lab tests showed the jab performed more poorly against the new variant.
The company has offered South Africa 20-million doses by May, according to activist Rehad Desai, who says he has seen leaked email correspondence between the government and Moderna. This comes after Moderna initially told the government it wasn’t interested in registering its vaccine for use in South Africa, Health Minister Zweli Mkhize said in December.
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Meanwhile, the country is expected to know in just days whether scientists working on the J&J vaccine trial can begin giving the jab to healthcare workers in the country as part of an expanded study, trial researcher and Medical Research Council president Glenda Gray says.
Although the J&J was 57% effective at preventing moderate to severe Covid-19 caused by the variant, it was even better at guarding against severe and critical Covid-19 cases across countries — variant or no variant, Gray explains.
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Meanwhile, time is of the essence for South Africa. The country’s current AstraZeneca vaccine stocks will expire in early April unless the provider, the Serum Institute of India, can either send new stock or advise South Africa it can safely extend the vaccine’s shelf life.
What You Need To Know About AstraZenecaÂ
- The vaccine is safe to use but did not show significant protection against mild or moderate Covid-19 when tested against the Covid-19 variant common in South Africa.
- The South African AstraZeneca study could not tell scientists if the vaccine could protect against severe Covid-19, deaths or hospitalization, because the sample size was too small, and people in it were largely healthy.
- The trial could also not detect any protection against Covid-19 that was less than 60%. A vaccine that could halve a person’s risk of mild to severe Covid-19 for at least six months would meet the World Health Organization (WHO) minimum vaccine requirements.
Still, Madhi says, there are limits to what the AstraZeneca vaccine trial could or couldn’t show. For instance, it wasn’t designed to detect any reductions in Covid-19 risk of less than 60%. And the AstraZeneca jab may yet still show promise in preventing severe Covid-19.
