Why the coronavirus variant has put a damper on vaccines in South Africa and why many are still hopeful

Why the coronavirus variant has put a damper on vaccines in South Africa and why many are still hopeful

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But scientists and vaccine manufacturers say the data has not yet had the final say, and there is still reason to be hopeful.

But the study, which has not yet been published, included a relatively small number of people who were generally young and healthy. It is important not to measure how effective the vaccine is against serious illness, hospitalization or death.

Dr Anthony Fauci said earlier that it is important to keep people out of the hospital from a public health perspective.

“If you can prevent serious illness in a high percentage of individuals, it will alleviate so much stress and human suffering and death,” Fauci said during a call with reporters last month.

While researchers in South Africa are still studying the impact of the vaccine on hospitalization there, AstraZeneca believes it will be effective against the variant in terms of serious diseases, a spokesperson told CNN on Sunday.

Until more data is available, scientists are compiling the puzzle with findings from clinical trials and the laboratory, each offering a different but incomplete view of how the variant could affect Covid-19 vaccines.

Clinical trials in South Africa

Prior to the announcement of AstraZeneca, Johnson and Johnson and Novavax had lower vaccine efficiencies in South Africa.

Novavax recently announced that its vaccine is 89% effective against the symptomatic Covid-19 in a Phase 3 study in the UK, but it appears to be only 49% effective in a separate Phase 2b study conducted in South Africa. Africa is done. The latter has risen to 60% when looking only at HIV-negative individuals.
Similarly, the effectiveness against moderate to severe disease in Johnson & Johnson’s phase 3 trial differed by country: 72% in the USA compared to 57% in South Africa.
Johnson & Johnson Covid-19 vaccine is 66% effective in worldwide trials, but 85% effective against serious diseases, says the company

In both trials, 90 to 95% of the cases in South Africa were linked to the variant, also known as B.1.351.

The silver lining: Johnson & Johnson’s trial showed that the single-shot vaccine was effective against serious diseases.

Mathai Mammen, the global head of research and development, told CNN earlier: “In all geographical countries, in all variants, we see 85% protection” against serious diseases. Plus, from one month after the shot, all hospitalizations and deaths occurred in the placebo group.

These results from Johnson & Jonhson also have hope for AstraZeneca.

“These two vaccines use a similar kind of technology,” said Dr. Shabir Madhi, professor of vaccination at the University of the Witwatersrand in South Africa, told the BBC on Monday.

Both vaccines use a different type of virus – an adenovirus – as a shell that carries genetic instructions into the human body, leading to an immune response. Johnson & Johnson uses a weakened common cold adenovirus, while AstraZeneca has changed one from chimpanzees.

“So I think it extrapolates from that. There is still some hope that the AstraZeneca vaccine can perform well as well as the Johnson & Johnson vaccine in another age group, which is at risk of serious diseases,” Madhi said.

Laboratory research

While clinical trials have provided a glimpse into the efficacy of vaccines, laboratory research has focused on the malady of the variant at a level that is invisible to the naked eye.

Coronaviruses are known to mutate, usually in ways that are harmless to humans. But every now and then a mutation appears that makes scientists look twice. These mutations can cause changes in the protein – the protein that the coronavirus uses to attach to and infect human cells. The ear protein is also an important target of the antibodies we create in response to vaccines.

A number of laboratory studies have suggested that antibodies from vaccinated humans are less effective in “neutralizing” the variant of infection of cells in the laboratory. But that does not mean that the virus has completely escaped.
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Oxford’s announcement this week states that neutralizing activity against B.1.351 “has been significantly reduced compared to the original coronavirus strain.”

Similar results have been seen, albeit to varying degrees, on ‘almost every one of the vaccines studied against this variant in different ways, whether in the laboratory or in clinical studies’, Drs. Salim Abdool Karim, chairman of the South African government’s advisory panel on coronavirus, told CNN earlier.

Many laboratory studies have looked at synthetic viruses designed to carry key mutations in B.1.351, while some research has tested the complete live virus. Experts believe that the latter provides a more complete picture of how the variant’s mutations can vary with each other and have joint effects.
Scientists have often focused on a mutation called E484K, which apparently helps the variant to escape the protection that antibodies provide. This mutation is also part of the genetic signature of the P.1 variant that was first linked to Brazil, and it is in a handful of cases of another variant that is common in the United Kingdom.

The problem with laboratory studies, however, is that it is difficult to know whether less neutralization in the laboratory means less protection in real life.

Coronavirus strain in the UK takes on mutation that could affect vaccines, experts say

“If you look at the studies that were done in laboratories, there was less neutralizing activity against the South African tribe,” said dr. Vaccine expert Paul Offit told CNN after Novavax and Johnson & Johnson shared their results. These trials apparently confirmed earlier findings of the laboratory.

Offit, which advises the U.S. Food and Drug Administration on vaccines, said the two vaccines currently granted in the U.S. – Moderna and Pfizer – could also be slightly less effective against the variant. Last year, these two vaccines showed 94% efficacy against the symptomatic Covid-19, with perhaps even higher efficacy against severe cases. But these results came largely before it was known that variants like B.1.351 were widely distributed.

For the time being, much of what we know about the efficacy of Moderna and Pfizer versus the variant comes from laboratory research. Both companies have indicated that they believe their vaccines will continue to protect against the variant.

“It’s really hard to compare numbers now from head to head without conducting a two-vaccine study,” said Moms of Johnson & Johnson.

Booster shots

However, the spotlight on antibodies can omit much of the complexity of our immune systems – which can adapt to threats such as coronavirus and recruit other cells for the fight, including T cells.

“You can not see all the breadth by just looking at antibodies,” said Marion Pepper, associate professor in the Department of Immunology at the University of Washington.

Yet many of the key players are developing tools to combat variants such as B.1.351, which are found in more than 40 countries and territories around the world, including a handful of cases in the US.

Moderna has announced that it will test two separate enhancers to its current two-shot regimen: an additional uptake of the currently authorized vaccine, and one specifically tailored for B.1.351. Pfizer also said it was “laying the groundwork” to create a vaccine booster.

Last month, Novavax began the following iterations of the vaccine, taking the form of a booster or a combined ‘divalent’ vaccine. Johnson & Johnson, whose phase 3 data comes from the one-vaccine vaccine, is also testing a two-shot regimen.

Similarly, Oxford and AstraZeneca think ahead.

“Efforts are being made to develop a new generation of vaccines that could reduce protection to emerging variants as boosters, if deemed necessary,” said Sarah Gilbert, professor of vaccination at Oxford University. said in a statement Sunday. “We are working with AstraZeneca to optimize the pipeline needed for voltage change should it become necessary.

“This is the same problem facing all vaccine developers, and we will continue to monitor the emergence of new variants that are ready for a future stress change.”

But there is no reason to wait until a new generation of vaccines gets one. On the contrary, experts believe the emergence of variants makes the vaccine more timely: the more people are vaccinated, the more hospitalizations can be prevented, and the less likely the virus is to mutate.

“You need to be vaccinated if it is available as quickly and as quickly as possible across the country,” Fauci said in a virtual newsletter on Monday. “Viruses cannot mutate if they do not repeat. And if you stop their replication by vaccinating widely, you will not get any mutations.”

CNN’s Elizabeth Cohen, Jamie Gumbrecht, Jacqueline Howard, Maggie Fox and Naomi Thomas contributed to this report.

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