- Pfizer Covid vaccine: what has the trial found and is this a breakthrough?
- What are the new results?
- How does this vaccine work?
- How excited should we be?
- How soon could it be available in the UK and globally?
- And what about the other vaccines – is Oxford far behind?
- A leading potential coronavirus vaccine just started human trials in the US. The top scientist at Pfizer told us it could be ready for emergency use this fall
- Pfizer is preparing for emergency use this fall
- Pfizer is ramping up production, with the possibility of producing billions of doses
- The coronavirus is 'very ly' to stay with us for years, Dolsten says
- What Pfizer’s landmark COVID vaccine results mean for the pandemic
- Questions remain
- Lasting immunity?
Pfizer Covid vaccine: what has the trial found and is this a breakthrough?
Pfizer and the German biotech company BioNTech said on Monday that they had had encouraging early results from a phase 3 clinical trial of their coronavirus vaccine. The trial is assessing how well the vaccine works in preventing humans from becoming infected. Although details are scant, the news is positive.
What are the new results?
Pfizer and BioNTech say they looked at 94 cases of coronavirus that occurred among participants after they had received two shots of either the vaccine or the placebo, and found that the vaccine was more than 90% effective at seven days after the second dose. As the two doses are spaced by three weeks, the team behind the vaccine say their results suggest protection is achieved 28 days after the initiation of the vaccination.
They also found no signs of safety concerns, and stressed that the participants were from diverse backgrounds – an important consideration given that black and ethnic minority groups appear to be at greater risk from the virus.
Regulators have previously said they would give the green light to a vaccine that has at least a 50% effectiveness rate, a bar this vaccine looks on course to exceed.
How does this vaccine work?
The vaccine in question is genetic material called mRNA that enables the production of the “spike proteins” that sit on the outside of the coronavirus. The vaccine introduces this mRNA to the human body, triggering human cells to produce the spike protein. In response to these proteins, the body produces antibodies, and other immune pathways are activated, guarding against infection.
How excited should we be?
Most experts agree that the results are exciting and excellent news, but the optimism should come with a note of caution: the results are preliminary, have been shared only by press release, and the trials are not yet complete.
Covid vaccine tracker: when will a coronavirus vaccine be ready?
So far, 38,955 people have received two doses of the vaccine, and the team plan a further analysis of the results once a total of 164 confirmed Covid-19 cases have occurred among the participants. They will also follow participants for two years post-vaccination to explore long-term safety and whether it continues to provide protection.
There are certainly still many questions that need to be answered, including how long protection via the vaccine might last, whether it protects those who have previously had coronavirus, and whether it prevents people from catching the virus and passing it on or simply reduces the severity of symptoms.
There are also logistical challenges, not least as the vaccine needs to be stored at -80C, meaning that even in developed countries there could be difficulties in distributing the jab.
However, the results so far are very encouraging. What’s more, if successful, the vaccine would be the first licensed jab to be mRNA, a development that could fuel the emergence of new vaccines for other diseases. It would also set a record for the shortest time taken to develop an effective vaccine from scratch.
How soon could it be available in the UK and globally?
There is some way to go before the vaccine will be available, as it must be approved by licensing authorities. Pfizer has said it plans to apply to the US Food and Drug Administration (FDA) for emergency approval as soon as safety data allows, possibly as soon as the third week of November.
In the UK, Boris Johnson’s spokesman has said the UK has secured 40m doses of the vaccine, 10m of which are due to be available before the end of the year assuming no snags.
But the logistical requirements mentioned above, such as cold storage, mean there could be problems rolling out the vaccine in countries with poorer health infrastructure or where electricity supply is unreliable, or in some rural areas.
In addition, while demand has been anticipated, a huge level of production will be required, and then there is the matter of who gets the vaccine first and how mass vaccination would be rolled out.
And what about the other vaccines – is Oxford far behind?
There are more than 170 vaccines in development, 11 of which are in phase 3 efficacy trials – including an mRNA vaccine from the US company Moderna, and the Oxford University/AstraZeneca vaccine.
The latter uses a different strategy to the Pfizer/BioNTech approach, delivering the gene for the spike protein to human cells via a chimpanzee cold virus that has been changed so it cannot grow and cause an infection.
The results from this vaccine trial are expected in a matter of weeks.
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A leading potential coronavirus vaccine just started human trials in the US. The top scientist at Pfizer told us it could be ready for emergency use this fall
A set of promising potential coronavirus vaccines just started trials in healthy volunteers in the US. If one of the injections works, the developers said they aim to make it available this fall.
The first trial participants were given the vaccines at the medical schools of New York University and the University of Maryland, the vaccine's developers, Pfizer and BioNTech, said in a statement.
Mikael Dolsten, Pfizer's chief scientific officer, told Business Insider in an interview that the testing plan could allow for emergency use or accelerated approval this fall. Dolsten acknowledged the unprecedented nature of this timeline for vaccine development, a process that typically requires multiple years of studies.
“I don't think this has ever happened in the history of modern vaccines,” Dolsten said, adding that nothing in his three decades of working in the drug industry matches the speed of this program.
Pfizer, a top drugmaker with a market value north of $200 billion, is leading the research in collaboration with the smaller biotech BioNTech. The human study is simultaneously testing four vaccine candidates at various dose strengths.
There are more than 100 coronavirus vaccines in development, with at least 20 expected to start human testing in 2020. The urgency of the pandemic has pushed drugmakers to reconsider the typical, multiyear timeline of vetting a vaccine before widespread use.
All four Pfizer-BioNTech vaccines were developed using the messenger RNA (mRNA) platform, an unproven vaccine technology that has taken center stage in the sprint for a coronavirus cure. The technology is marked by its speed, requiring just the genetic code of the virus to build a vaccine candidate.
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But mRNA has yet to produce an approved vaccine, leaving COVID-19 as a real-time test of the technology on the biggest possible stage.
The Massachusetts biotech Moderna is also testing an mRNA coronavirus vaccine candidate, which was the first to enter the clinic earlier this year. Moderna is eyeing the potential for emergency use this fall as well.
For now, both vaccine programs remain in the earliest stages of human testing. Pfizer and Moderna are both expecting initial trial results focused on safety in the next month or so.
Read more: Here's how 13 top drugmakers are sprinting to develop a coronavirus vaccine or treatment that can halt this pandemic
Pfizer is preparing for emergency use this fall
Researchers are also now vaccinating primates with Pfizer's vaccine and then exposing them to the virus to see if they get infected. Dolsten said this work could support the vaccine and also help answer what immune response is required to protect people.
Researchers will measure the primates' blood for the level of antibodies needed to protect from disease.
“It gives you a very nice surrogate,” Dolsten said. “If you have a similar level in humans vaccinated, it's quite reasonable to assume it protects humans.”
The US human trials are part of a program also recruiting volunteers in Germany. The University of Rochester and Cincinnati Children's Hospital Medical Center will soon start enrolling volunteers for the study alongside the University of Maryland and NYU. The US study aims to recruit 360 healthy volunteers ranging from 18 to 85 years old.
Initial human results and strong data showing the vaccine works in animals could build the case for broader use in the fall.
A potential emergency use would ly depend on the dynamics of the pandemic, Dolsten said.
For instance, imagine a city at the epicenter of a fall outbreak. Pfizer could vaccinate the northern part of that city, wait a couple months, and then immunize the other half, assuming they have similar populations, Dolsten said.
That approach would not only collect data on tens of thousands of people, clarifying the benefits and risks from the experimental vaccine, but it could help address a public health crisis in real time.
Using a so-called surrogate endpoint, the level of neutralizing antibody that people develop after getting an injection, could allow research to enter this phase of testing “many months earlier,” Dolsten said. Researchers would still want to see that the vaccine prevents people from getting infected, which additional studies would determine.
Others have cautioned that there are many unknowns surrounding the immune response to this virus. While animal data may suggest protection from a certain level of antibodies, that isn't necessarily proof it will protect humans.
Read more: There are more than 100 potential coronavirus vaccines in the works. Here are the top efforts to watch, including the 20 programs expected to start human trials this year.
Pfizer is ramping up production, with the possibility of producing billions of doses
Pfizer and BioNTech are now scaling up manufacturing to prepare to meet demand if their vaccine works.
Pfizer has plants in Massachusetts, Michigan, Missouri, and Belgium to produce the vaccine. BioNTech has two plants in Germany.
Dolsten said they expect to have millions of doses available by October, progressing to 10 million to 20 million doses available later in 2020. In 2021, they plan to have “hundreds of millions” of doses available.
“There is a possibility that we could go to billions,” Dolsten said. “We would certainly welcome collaborations to bring us to that scale.”
Read more: 4 top drugmakers are betting they can make effective coronavirus treatments much faster than a vaccine
The coronavirus is 'very ly' to stay with us for years, Dolsten says
Pfizer's top scientist said the world should be preparing for the potential for another wave of coronavirus this fall.
“It's very possible and very ly that this virus will stay with us for many, many years,” he said. “Unfortunately, we have to be prepared that coronaviruses are here and are going to be a formidable enemy and really a medical nuisance.”
“Nobody would be happier than us if we are proven wrong,” Dolsten added. “But we cannot afford to plan for optimism. We need to plan for multiple scenarios and hope for the best.”
What Pfizer’s landmark COVID vaccine results mean for the pandemic
Credit: Eva Marie Uzcategui/Bloomberg via Getty
It works! Scientists have greeted with cautious optimism a press release declaring positive interim results from a coronavirus vaccine phase III trial — the first to report on the final round of human testing.
New York City-based drug company Pfizer made the announcement on 9 November. It offers the first compelling evidence that a vaccine can prevent COVID-19 — and bodes well for other COVID-19 vaccines in development.
But the information released at this early stage does not answer key questions that will determine whether the Pfizer vaccine, and others it, can prevent the most severe cases or quell the coronavirus pandemic.
“We need to see the data in the end, but that still doesn’t dampen my enthusiasm. This is fantastic,” says Florian Krammer, a virologist at Icahn School of Medicine at Mount Sinai in New York City, who is one of the trial’s more than 40,000 participants. “I hope I’m not in the placebo group.”
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The vaccine, which is being co-developed by BioNTech in Mainz, Germany, consists of molecular instructions — in the form of messenger RNA — for human cells to make the coronavirus spike protein, the immune system’s key target for this type of virus.
The two-dose vaccine showed promise in animal studies and early-stage clinical trials. But the only way to know whether the vaccine works is to give it to a large number of people and then follow them over weeks or months to see whether they become infected and symptomatic.
These results are compared with those for a group of participants who are given a placebo.
In the press release, Pfizer and BioNTech said they had identified 94 cases of COVID-19 among 43,538 trial participants. The companies did not indicate how many of those cases were in the placebo group or among those who got the vaccine.
But they said that the split of cases between the groups suggested that the vaccine was more than 90% effective at preventing disease, when measured at least one week after trial participants had received a second vaccine dose 3 weeks after the first.
The trial will continue until a total of 164 COVID-19 cases are detected, so initial estimates of the vaccine’s effectiveness could change.
Although the vaccine might not turn out to be quite so effective once the trial is complete and all the data have been analysed, its effectiveness is ly to stay well above 50%, says Eric Topol, a cardiologist and director of the Scripps Research Translational Institute in La Jolla, California.
This is the threshold that the US Food and Drug Administration (FDA) says is required for a coronavirus vaccine to be approved for emergency use.
“I think this is an extraordinary achievement, even without many details, because there was no assurance of vaccine efficacy before we got the first read-out from a trial,” Topol says.
What’s missing, say Topol and other scientists, are details about the nature of the infections the vaccine can protect against — whether they are mostly mild cases of COVID-19 or also include significant numbers of moderate and severe cases.
“I want to know the spectrum of disease that the vaccine prevents,” says Paul Offit, a vaccine scientist at the Children’s Hospital of Philadelphia in Pennsylvania who sits on a US Food and Drug Administration advisory committee that is set to evaluate the vaccine next month.
“You’d to see at least a handful of cases of severe disease in the placebo group,” he adds, because it would suggest that the vaccine has the potential to prevent such cases.
It’s unclear whether the vaccine can prevent people who show no or only very mild symptoms of COVID-19 from spreading the coronavirus. A transmission-blocking vaccine could accelerate the end of the pandemic.
But it will be difficult to determine whether the Pfizer vaccine, or others in late-stage trials, can achieve this, says Krammer, because it would involve routinely testing trial participants.
“You can’t do that with 45,000 people,” he says.
Another missing detail is how well the vaccine works in different groups of trial participants. “We don’t know yet if it works in the population that needs it most, which is elderly,” says Krammer.
Because of the small number of cases it will accrue before ending, the Pfizer trial is unly to conclusively determine the vaccine’s efficacy in particular demographic groups, such as over-65s or African Americans, says Offit.
But he adds that if the trial enrolled enough participants from such groups, it could be possible to generalize the vaccine’s probable effectiveness in them from its overall efficacy. In the press release, Pfizer and BioNTech reported that 42% of participants had “racially and ethnically diverse backgrounds”.
One key unanswered question is how long the vaccine’s effectiveness will last.
On the basis of when the trial started and previously published data on immune responses in early-stage trials, many trial participants are ly to still have high levels of protective antibodies in their blood, says Rafi Ahmed, an immunologist at Emory University in Atlanta, Georgia. “To me, the main question is what about six months later, or even three months later,” he says.
There will be a chance to answer that question if the trial continues for several more months, says Ahmed.
Answers could also come from analysis of the immune responses of people who took part in early-stage trials of the Pfizer vaccine, some of whom might have been given the vaccine up to six months ago.
And although little is known about the vaccine’s long-term effectiveness, that is unly to hold up its use, says Ahmed. “I don’t think we should say, ‘Well, I’ll only take a vaccine that protects me for five years.’ I mean, that could be crazy.”
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The results are a boost for other COVID-19 vaccine candidates. That includes an mRNA vaccine being developed by Moderna, a biotechnology company in Cambridge, Massachusetts, and the US National Institute of Allergy and Infectious Diseases in Bethesda, Maryland, says Krammer. “I expect Moderna stocks will go up today.”
Shane Crotty, a vaccine immunologist at the La Jolla Institute for Immunology in California, thinks that Moderna isn’t the only developer that should celebrate Pfizer’s preliminary results. Several other candidate vaccines triggered immune responses similar to those elicited by Pfizer’s vaccine in early-stage trials, so they should work well, too.
One thing about Pfizer’s vaccine is certain: regulators will soon decide whether it’s ready for roll-out. The company said it would seek an emergency use authorization from the FDA around the third week of November, at which point half of the participants will have been followed for two months — an FDA safety requirement for COVID-19 vaccines.
And although researchers want to see the data behind Pfizer’s vaccine trial, they are prepared to accept caveats that come with them. “Right now, we need a vaccine that works,” says Krammer, even if it works for only a few months or doesn’t stop transmission. “That’s what we need in order to get half-way back to normal.”