Picture: Justin Tallis/AFP
Picture: Justin Tallis/AFP

SA is switching shots but experts say AstraZeneca and J&J vaccines are similar

By Kelly Jane Turner Time of article published Feb 11, 2021

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Cape Town – As South Africa switches shots from the AstraZeneca vaccine to the Johnson & Johnson vaccine, some experts say the country should still pursue its initial option because the two vaccines are not so different.

Professor Shabir Madhi from the University of the Witwatersrand and lead investigator in the South African trial of AstraZeneca's vaccine says the shot will still be effective against severe Covid-19 infection.

“The AstraZeneca vaccine is almost identical to the Johnson & Johnson vaccine in terms of the technology and the immune response. Biologically, it is highly plausible that the vaccine will work the same when tested in the same conditions,” he said.

“The vaccines were captured in very different populations and they were captured in different conditions. The Johnson & Johnson vaccine mainly tested for moderate and severe disease. The AstraZeneca vaccine is mainly tested for mild infection. Both of them will probably not work for mild infection, but both of them will probably work for severe disease.”

The Department of Health said in an online briefing on Sunday the rollout of the AstraZeneca vaccine which had been scheduled to begin in the country this month is now on temporary hold. A study showed the vaccine gave minimal protection against mild-to-moderate infection caused by the country's dominant coronavirus variant.

In a statement released on Wednesday evening, Cabinet reassured South Africans the vaccine rollout remains on track and the Johnson & Johnson vaccine would be used instead of the AstraZeneca vaccine.

“This change follows the comprehensive research conducted by medical scientists which showed that the AstraZeneca had a minimal efficacy against the Covid-19 501Y.V2 variant. The Johnson & Johnson vaccine has proven effective against the 501Y.V2 variant that is predominantly found in the country.

At the same time, the Strategic Advisory Group of Experts on Immunisation (SAGE) said during an online World Health Organization (WHO) press briefing the benefits of the AstraZeneca vaccine outweighed any risks and the shot should be recommended for use, including in people aged 65 and older.

According to a WHO statement: “SAGE has reviewed all available data on the performance of the vaccine in the settings of variants of concern. SAGE currently recommends the use of AZD1222 vaccine according to the WHO Prioritization Roadmap, even if virus variants are present in a country. Countries should assess the risks and benefits taking into consideration their epidemiological situation.”

Here’s how the AstraZeneca vaccine and the Johnson and Johnson vaccine compare:


  • Is a two-dose regimen, 4 weeks apart
  • 22% efficacy in South Africa
  • Clinical trial from Wits University examined 2 000 volunteers where the median age was 31. Vaccine found to offer limited protection against B.1.351 variant
  • Viral vector vaccine technology that uses a genetically modified and harmless version of a common cold viral vector (known as an adenovirus) from chimpanzees.
  • Can be kept in regular refrigerators between 2°C and 8°C

Johnson and Johnson vaccine:

  • One-dose regime
  • 57% efficacy in South Africa and proven to work against B.1.351 variant
  • Trial with participants from the United States, Latin America and South Africa had 44 325 people enrolled and overall efficacy was 85% effective in preventing severe disease and hospitalisation.
  • J&J’s vaccine uses the same type of “viral-vector” technology that’s used in the shot developed by AstraZeneca.
  • Can also be kept in regular refrigerators between 2°C and 8°C

The Johnson and Johnson vaccine will not be produced in South Africa by Aspen Pharmacare in Port Elizabeth, however, the company is one of six sites globally responsible for putting the vaccine into vials and packaging the jabs for distribution.

“The ability to do a fill and finish, helps South Africa gain access to any other vaccines,” said Madhi.

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