The race is on to find a vaccine for COVID-19, with pharmaceutical companies across the world working around the clock to develop their own effective, safe candidates.
This week it emerged that early results from the latest stage of testing for AstraZeneca and the University of Oxford’s possible vaccine showed a “strong immune response... across all age groups” - the latest in a flurry of announcements about progress to vaccines in development.
There are currently 260 vaccines being tracked by the London School of Hygiene and Tropical Medicine, according to AFP, with 11 in large-scale phase three trials.
So which ones are closest to being ready and what are they?
Pfizer and German partner BioNTech SE were the first companies to show successful data from a large-scale clinical trial of a coronavirus vaccine, announcing earlier in November that it was more than 90% effective.
This week, the company said trials showed the messenger RNA (mRNA) vaccine, which only uses the virus’s genetic code, protected 95% of trial participants within four weeks of receiving the first dose.
The vaccine, which is administered in two doses, also appears to protect 94% of people over 65-years-old, and works equally well across all ethnicities and races of people, the company said.
Pfizer said there had been “no serious safety concerns” reported - only that 2% of the 43,000 people testing the vaccine said they had experienced a headache, and 3.7% had reported fatigue.
The company is now planning to apply for emergency-use authorisation from the US Federal Drug Administration.
US company Moderna announced on November 16 that interim trial results showed its coronavirus vaccine may be 94.5% effective against COVID-19.
More than 30,000 people in the US took from a range of age groups and ethnic backgrounds took part in the trial for the mRNA vaccine.
Two doses were given, 28 days apart, so researchers could evaluate safety and any reaction to the vaccine.
The analysis included 95 participants with confirmed cases of COVID-19, of which 90 received a placebo vaccine and five the active vaccine.
Moderna also released data relating to severe cases, saying interim analysis included 11 such patients who all occurred in the placebo group and none in the group which had received the vaccine.
Watch: How will a coronavirus vaccine be administered?
Early results from the latest stage of testing for AstraZeneca (AZN.L) and the University of Oxford’s possible COVID-19 vaccine show a “strong immune response... across all age groups.”
AstraZeneca said interim results from its Phase II/III trial, which involves almost 13,000 people in the UK and 60,000 people around the world, showed patients given the vaccine exhibited a “robust immune response.”
Patients who received the vaccine experienced some “mild, local and systemic reactions,” such as pain in the injection site and headaches. Older patients who received the vaccine showed less symptoms than young participants, the company said.
AstraZeneca said it was inconclusive whether the vaccine generated a lasting immunity to COVID-19 for patients who receive it.
UK health secretary Matt Hancock said the results were a “really encouraging set of findings.” Earlier this year Britain signed a deal to buy 100 million doses of the AstraZeneca and University of Oxford vaccine if successful.
US-based biotechnology firm Novavax launched its Phase 3 clinical trial of potential COVID-19 vaccine NVX-CoV2373 in the UK on 23 September.
The first participants enrolled at the new NIHR (National Institute for Health Resarch) centre in Blackpool five days later.
Brought to the UK in collaboration with the UK Government’s Vaccines Taskforce, the Novavax trial was set to recruit up to 10,000 participants aged 18 to 84 years.
A parallel Phase 3 study was due to start in the final quarter of 2020 in the US, the NIHR said, saying the UK study could get underway sooner thanks to “advanced research infrastructure already in place within the UK”, including its own National Patient Recruitment Centres and the NHS Vaccine Research registry.
Jansson/Johnson & Johnson
Johnson & Johnson (JNJ) subsidiary Janssen started its clinical trials of a potential vaccine on November 16, involving 6,000 volunteers across the country, co-funded by the government’s Vaccine Taskforce.
The vaccine started its Phase 3 trial in September, including 60,000 people across the US, Argentina, Brazil, Chile, Colombia, Mexico, Peru and South Africa.
Announcing the start of further UK clinical trials, Business Secretary Alok Sharma said: “The start of further clinical trials in the UK is yet another step forward in the race to discover a safe and effective vaccine, and comes alongside recent news that we could be on the cusp of the first major breakthrough since the pandemic began.”
The government has developed a portfolio of six different vaccine candidates and secured access to 350 million doses to date.
Of this, 30 million doses of the Janssen vaccine could be made available to the UK, if it is safe and effective, by mid-2021.
In June CanSino became the first company to receive limited approval to use its viral vector vaccine in people and the Chinese government previously approved it for military use only.
Results from the Phase II trial showed that the vaccine produces “significant immune responses in the majority of recipients”, with no serious side effects.
Mexico has received doses of the vaccine candidate for late stage-trial on 10,000 and 15,000 volunteers.
But critics have voiced concern that the effectiveness of the vaccine, which is based on a common cold virus, could be limited.
Russia’s vaccine, Sputnik V, uses two strains of adenovirus and requires a second follow-up injection after 21 days to boost the immune response.
The Gamaleya Research Institute has claimed that the vaccine is 92% effective, with 20 of 16,000 volunteers who received the vaccine contracting COVID-19.
Despite a short pause, Russia has forged ahead with the vaccination of new volunteers in its trial for the drug, as part of plans to innoculate its population.
Beijing Institute/Sinopharm & Wuhan Institute/Sinopharm
Vaccine candidates are being jointly developed by the Beijing Institute of Biological Products and the Wuhan Institute of Biological Products – subsidiaries of the SinoPharm unit, China National Biotec Group (CNBG).
The vaccines, which use inactivated virus unable to replicate in human cells to trigger immune responses and require two doses, are undergoing Phase 3 clinical trials overseas.
China National Pharmaceutical Group (Sinopharm) said last week that data from late-stage clinical trials were “better than expected”.
Nearly one million people have taken the experimental vaccine through the country’s emergency use programme, the firm said this week.
China launched its emergency use programme in July, which reportedly includes three vaccine candidates for essential workers and other limited groups of people despite clinical studies yet to be completed to prove their safety and efficacy.
Covaxin, the vaccine candidate developed by Bharat Biotech in collaboration with the Indian Council of Medical Research (ICMR), has moved into Phase 3 trials.
Set to involve 26,000 volunteers across India, it is the largest clinical trial conducted for a Covid-19 vaccine in India.
As part of the trial, volunteers will receive two injections approximately 28 days apart.
Organisers say participants will be randomly assigned to receive either Covaxin or a placebo and the trial is double blinded — with investigators, participants and the company not be aware of who is in which group.
China’s Sinovac vaccine, Coronavac, has reportedly shown success in mid-stage trials, leading to a quick immune response during trials with around 700 people, according to a paper published in scientific journal The Lancet.
Sinovac is currently running three Phase III trials in Indonesia, Turkey and Brazil - where they were briefly paused due to the death of a study subject that was registered in Sao Paulo as a suicide but have now resumed.
Preliminary results suggest the vaccine triggers a quick immune response, although the level of antibodies produced was lower than in people who had recovered from the disease.
One researcher called the vaccine ‘an attractive option’ because it can be stored at normal fridge temperatures and may remain stable for up to three years, unlike the Pfizer vaccine which can only be kept in a normal fridge for up to 5 days, or Moderna's, which is expected to last for 30 days at normal fridge temperatures.
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