Covid-19 vaccines must be compared to ensure 'most effective are used'

Covid-19 vaccines must be compared to ensure 'most effective are used'

Different Covid-19 vaccines must be thoroughly compared to ensure only the most effective are used, Oxford University experts say

  • Scientists said comparisons should consider factors around supply of vaccine
  • More than 200 are in development – but only nine have entered final trials
  • It is hoped that at least one vaccine will report before Christmas this year

Different Covid-19 vaccines must be compared to ensure only the most effective are used, experts at Oxford University have said. 

Researchers said it is unlikely ‘we will see a single vaccine winner in the race against Covid-19’.

They warned that each candidate is likely to have its own ‘distinct’ advantages due to differences in design. And the team admitted there will ‘probably be challenges with manufacturing and supplying a single vaccine at the scale required’.  

In a review published in The Lancet Infectious Diseases journal, the scientists said a meaningful comparison of different candidates is required to ensure only the most effective vaccines are deployed.   

More than 200 Covid-19 vaccines are being trialled worldwide, including nine which entered the final stage of experiments — where they are given to tens of thousands of people to determine their safety and effectiveness.

An effective vaccine is one that can act against infection, disease, or transmission – potentially keeping the Covid-19 pandemic under control. Top experts say a vaccine that works is likely to be the only way the world can safely return to life before the pandemic.

It comes after Imperial College London’s Professor Wendy Barclay claimed a vaccine could provide protection that lasts much longer than natural immunity. She said this was because the vaccines are using weakened forms of the virus which, unlike a full blown infection, can’t inhibit the body’s immune response.

A vaccine may be rolled out to NHS staff before Christmas, according to reports this weekend, before being made available to others at the start of 2020. An email sent to staff at George Eliot Hospital NHS Trust in Warwickshire by its chief executive advises employees to be ready for vaccination ‘in early December’.

Experts said that all vaccines developed should be compared to ensure only the most effective are used – as more than 200 are currently in development (stock)

UK DRUG WATCHDOG PLANS TO FAST-TRACK 

The UK’s drugs watchdog has started the rolling review process of a coronavirus vaccine being developed by US pharmaceutical giant Moderna, the firm announced.

This means health officials will review data as it becomes available from ongoing studies before a formal application for approval is submitted.

It normally takes years for vaccines to be green-lit by the Medicines and Healthcare products Regulatory Agency (MHRA) as it pores over data to make sure jabs will be safe and effective to dish out to millions of Brits. 

But, by reviewing the findings in real-time, the regulator can fast-track it through the process.

Moderna’s vaccine candidate – called mRNA-1273 – is one of the global frontrunners, along with a jab being developed by Oxford University. 

The UK Government has announced frontline health and care workers, and those at an increased risk of serious disease, including elderly care homes residents, will be first in line to get access to a vaccine.

On Monday, Health Secretary Matt Hancock refused to rule out getting the vaccine to these groups before Christmas. Though he admitted the likely timeframe was early next year.      

Dr Susanne Hodgson, lead author of the review published in The Lancet Infectious Diseases journal, and an infectious diseases expert at the University of Oxford, said: ‘It is unlikely that we will see a single vaccine winner in the race against Covid-19.

‘Different technologies will bring distinct advantages that are relevant in different situations, and additionally, there will probably be challenges with manufacturing and supplying a single vaccine at the scale required, at least initially.

‘Taking a standardised approach to measuring the success of vaccines in clinical trials will be important for making meaningful comparisons, so that the most effective candidates can be taken forward for wider use.’ 

The review authors add that ‘standardised, quantifiable endpoints’ need to be set out for comparing vaccines in clinical trials, and the ‘limitations and potential for bias’ should be understood. 

They also said long-term follow-up of the Covid-19 vaccine recipients will be needed to evaluate efficacy against severe disease and mortality as well as to ensure the ongoing evaluation of vaccine safety.

Review co-author Dr Kate Emary, also of the University of Oxford, said: ‘To determine whether a vaccine protects against severe Covid-19 disease, a clinical trial needs to show that there are significantly fewer cases of severe disease in individuals vaccinated with a Covid-19 vaccine, compared with individuals who are not.

‘However, only a small proportion of individuals infected with Sars-CoV-2 develop severe disease, which means an extremely large number of volunteers is needed in a clinical trial for there to be enough cases to get a reliable measure of vaccine efficacy.

‘This means that it is likely that we will only know if a vaccine protects against severe disease once it has been deployed and given to a large population.’

The authors also discussed controlled infection studies in humans, known as challenge trials, as a way to measure vaccine efficacy as coronavirus transmission declines in the community.

But they argued that while human challenge trials could allow rapid assessment of vaccine efficacy, ‘it is unclear if results from these studies – which are likely to only include young volunteers – will predict vaccine efficacy in older adults’.

Challenge trials are when volunteers – typically in low risk age groups – are deliberately infected with the virus before their response is closely monitored by doctors.

They are due to start in the UK early next year to help determine the effectiveness of vaccines. 

The review comes after the Government announced last week that it is putting £33.6m towards human challenge studies, with trials set to begin in early January 2021.

Race for a coronavirus vaccine: Nine candidates in final stage of clinical trials

As scientists race to develop a coronavirus vaccine to bring the world back to normal, MailOnline has taken a look at the prospective candidates.

Vaccine trials were halted on Wednesday but it may still be ready this year

The Oxford Vaccine

When will it be ready?: The end of 2020/ early 2021. Despite the trials being suspended on Wednesday, its developers and Number 10 remain confident that the vaccine could be ready for use either at the end of this year or early next year. They say a pause is common in trials, and that its development was also stopped in July after a suspected side-effect was detected.

How does it work?: The vaccine works by exposing participants to a weakened common cold adenovirus which has had proteins from the coronavirus SARS-CoV-2 attached to its surface. The idea is that the exposure allows the immune system to build an immune response, meaning they are protected if they are infected by the real virus. 

Has the UK secured doses?: Yes, 100 million. The US has secured a further 300 million doses, along with several other countries. These will be rolled out in an equitable manner.

How much does it cost?: AstraZeneca, which is developing the vaccine with Oxford University, has said it will not profit from the it, but may earn extra royalties if the coronavirus becomes an endemic infection like flu. The US has spent $1.2 billion (£930 million) securing doses, meaning they are worth $4 (£3.10) each.

Biontech, Germany

Biontech vaccine may be ready this year

When will it be ready?: At the end of this year, say researchers. The vaccine is being developed by a German company in partnership with American drugmaker Pfizer. It is recruiting 30,000 volunteers to its stage three trials.

How does it work?: This is an RNA vaccine, a type that has never been approved by regulators before. It will involve injecting a fragment of genetic material from coronavirus into participants. This will expose their immune systems to a weakened version of the virus and, hopefully, trigger a response which will protect them from the real virus.

Has the UK secured doses?: Yes, 30 million doses. The US has also ordered 100 million doses. 

Price?: The US is paying $2 billion (£1.5 billion) for its doses, or about $20 (£15) a jab.

Moderna, US

Moderna vaccine entered human trials

When will it be ready?: Very end of this year or next year. The vaccine has recruited 20,000 participants for its stage three trials. Providing no potential side effects are observed, it will then go through to a second test on more patients next month. This means it could be available by the end of 2020.

How does it work?: This is an RNA-based vaccine, similar to the one being developed by Biontech. 

Has the UK secured doses?: No. Reports suggest the UK’s task force has not managed to secure any doses of this vaccine.

How much does it cost?: The US has ordered 100 million doses at a price of $1.5 billion (£1.1 billion). This means one jab costs $32 (£25).

Sanofi and GlaxoSmithKline, UK and France

Sanofi vaccine won’t be available this year

When will it be ready?: First half of 2021. The vaccine entered phase two clinical trials in September, involving 440 adults. It will reach phase three trials in December this year. There may be setbacks along the way, meaning the vaccine could take longer to develop. 

How does it work?: Participants are injected with DNA coding for the antigens of the coronavirus and a chemical which makes it more potent. It is hoped this will trigger an immune response.

Has the UK secured doses?: Yes. Up to 60 million will be supplied should the vaccine be shown to work.

How much does it cost?: Unknown. This information has not been provided.

Sputnik V, Russia

Sputnik V is safe, according to Kremlin, but it has been criticised by scientists

When will it be ready?: ‘Imminently’. The Russian medical research institute and Russian defence ministry have developed this vaccine. But it has faced serious criticism both inside and outside Russia because results from its human trials are yet to be published. It also hasn’t cleared large human trials, with researchers only launching one involving 40,000 volunteers on 26 August. Scientists say the vaccine has been rushed without proper checks, and could pose a risk to those taking it. The Kremlin began appealing for volunteers for the vaccine this week after a first batch was produced, according to the TASS news agency.

How does it work?: The Russian vaccine works by carrying a piece of the coronavirus genetic code into a participant via another virus. It is hoped this will produce an immune response.

Has the UK secured doses?: No. Countries lining up to try the vaccine include Mexico, which has secured 32 million doses, and Kazakhstan, which is set to buy two million.

How much does it cost?: The price of the vaccine is yet to be revealed.

Sinovac, China

It is not clear when the Sinovac vaccine will be available

When will it be ready?: Unknown. The vaccine entered final-stage trials in Brazil in July, and then in Indonesia in August. Results show that while younger and middle-aged people produced antibodies, older people had a weaker immune response. The vaccine was given emergency approval for limited use in July, reports suggest, although it appears to still be subject to testing. It was previously reported as being second only to the Oxford vaccine, but its complete test results are yet to be published. It is one of four vaccine candidates in development in China.

How does it work?: It involves injecting patients with an inactivated form of the virus, prompting their immune systems to develop a response. 

Has the UK secured doses?: Unknown. Reports suggest no doses have been secured.

How much does it cost?: China is yet to publish this information.

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