Another Covid vaccine candidate reports promising results - what we know

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  • Results from the Oxford University Covid-19 vaccine trial shows promising results, with up to 90% efficacy reported
  • The vaccine will now await regulatory approval from independent regulator, the MHRA 
  • The UK government has pre-ordered 100 million doses, and AstraZeneca stated that it will seek an Emergency Use Listing from WHO for vaccine availability in low-income countries

Positive data from an interim analysis of the University of Oxford’s Covid-19 vaccine trial in the UK and Brazil shows that it protects 70% of people from developing Covid symptoms, Oxford's manufacturing partner, AstraZeneca announced on Monday.

The data is from the COV002 Phase 2/3 trial in the UK and COV003 Phase 3 trial in Brazil, which involves more than 23 000 participants. No hospitalisations or severe cases of the disease were reported in volunteers who received the vaccine, named AZD1222.

A total of 30 cases of Covid-19 were found in participants who received two jabs of the vaccine, and 101 cases in people who received a saline injection. According to the researchers, it translates to 70% protection.

Additional data from the large-scale trial also suggests that perfecting the dose could increase protection up to 90%. This was seen for one course of dosing, where volunteers received a half dose of the vaccine, followed by a full dose at least one month after.

When participants were given two "high" doses, it resulted in 62% protection. However, this increased to 90% when participants received a "low" dose followed by a high one. 

Chief investigator pleased with results

Professor Andrew Pollard, the trial’s lead investigator said: "Excitingly, we've found that one of our dosing regimens may be around 90% effective and if this dosing regime is used, more people could be vaccinated with planned vaccine supply."

The researchers stated that it's not clear why there is a difference, although Pollard told the BBC that the team is “really pleased with these results”.

There were also lower levels of asymptomatic infection in the low followed by high dose group which "means we might be able to halt the virus in its tracks," Pollard said.

Vaccine's architect Professor Sarah Gilbert also commented: “The announcement today takes us another step closer to the time when we can use vaccines to bring an end to the devastation caused by [the virus].”

The vaccine uses an adenovirus, which causes the common cold in chimpanzees, that has been genetically engineered so that it’s unable to replicate and cause disease in humans. 

How does the Oxford vaccine fare, compared to Pfizer and Moderna's vaccines?

This news follows shortly after the positive results announced by Pfizer/BioNTech and Moderna, whose vaccines showed 95% and 94.5% protection respectively. Both companies have applied to regulatory authorities for approval.

While 70% may seem like a disappointing result in comparison to these two vaccines, the Food and Drug Administration (FDA) requires a Covid-19 vaccine to prevent disease in 50% of volunteers in order to gain approval.

Logistics less complex

Logistics of storing and transporting the Oxford vaccine will be far less complex than the Pfizer and Moderna vaccines, as it can be stored at fridge temperature, making it more favourable to distribute worldwide.

The Pfizer/BioNTech vaccine needs to be stored below freezing temperatures (minus 70 degrees Celsius), while Moderna’s vaccine needs to be shipped and transported at minus 20 degrees Celsius.

Reporting by Bhekisisa earlier this month notes that despite its promise, cold chain requirements mean these jabs wouldn’t be the first choice for countries like South Africa.

In addition to the above, the Oxford vaccine is also much cheaper than the Pfizer and Moderna vaccines.

This means that it will play a significant role in fighting the spread of the virus, if it is approved by regulators, which is due to take place in the next couple of weeks.

"I'm really very pleased, I really welcome these figures - this data - that show that the vaccine in the right dosage can be up to 90% effective,” Health Secretary Matt Hancock told Sky News.

"Of course, it's vital that the independent regulator - the MHRA (Medicines and Healthcare products Regulatory Agency) - will need to look at the data, will need to check to make sure that it's effective and safe." 

Comments on results by lead investigator of SA's trial

Clinical trials are also being carried out in the US, Japan, Russia, South Africa, Kenya and Latin America. Planned trials are due to take place in other European and Asian countries. A total of 60 000 participants are expected to be enrolled globally.

This vaccine candidate was also the first of Covid-19 vaccines to be trialled in South Africa. Named the Ox1Cov-19 Vaccine VIDA trial, it is done in collaboration with Oxford University. The SA trial is being led by Shabir Madhi, Professor in Vaccinology at Wits University.

Commenting on the results, Madhi said in a press release by the university:

“The results from this study add further hope that accessing vaccines to fight the Covid-19 pandemic are fast becoming a reality.

"The results from this study are intriguing, in that a dose-sparing regimen may inadvertently end up being more protective. This has implications not only for the cost of the vaccine, but also how many more people could possibly be vaccinated in the near future when vaccine supply is likely to be constrained.

"Also, the ability to scale up production of this vaccine, and it only needing to be stored at 2-8 degrees Celcius, would greatly assist in the deployment of the vaccine in low- and middle-income countries. The cost of this vaccine is also anticipated to be much cheaper than other Covid-19 vaccines that have recently been shown to be efficacious.”

Madhi emphasised the importance of testing the vaccine in diverse populations, such as South Africa:

“The results of the study from South Africa remain of global interest, and to inform recommendations on Covid-19 vaccine in Africa, as the Covid-19 experience in South Africa has been very different to the UK.

"As for many other vaccines, genetic factors and local conditions could also affect the performance of the vaccine in different populations. The results of the pooled analysis from UK and Brazil creates optimism that we will also show protection against Covid-19 in the South African study, where participants are still being followed-up.”

Who’s first in line to receive the vaccine?

According to the BBC, AstraZeneca is preparing to produce three billion doses for the world next year.

The UK government has already pre-ordered 100 million doses, enough to immunise 50 million people. If approved, four million is expected to roll out by the end of the year.

Earlier this year, Madhi explained that AstraZeneca, however, doesn’t have any direct involvement with SA’s vaccine trial as the agreement to do the trial here preceded Oxford’s agreement with AstraZeneca for further clinical development and manufacturing of the vaccine.

But spokesman for the Department of Health, Popo Maja, confirmed to Spotlight this month that although SA had not concluded any vaccine deal, negotiations with manufacturers and COVAX (an initiative co-lead by the World Health Organization that aims to ensure developing countries get access to Covid-19 vaccines) are underway.

AstraZeneca’s press release notes that “it will now immediately prepare regulatory submission of the data to authorities around the world that have a framework in place for conditional or early approval.

“The Company will seek an Emergency Use Listing from the World Health Organization for an accelerated pathway to vaccine availability in low-income countries. In parallel, the full analysis of the interim results is being submitted for publication in a peer-reviewed journal,” they stated.

READ | Covid-19: Two of the vaccine front runners have already reported promising evidence - so what now?

READ | Cold truth: South Africa won’t be able to store these Covid vaccines. Here’s why.

READ | The latest news on a leading Covid vaccine candidate is promising, but how optimistic should we be?

Image: Getty/zhangshuang

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