With more than 20 Covid-19 vaccine trials happening around the world, scientists are working flat out to find a preventative measure for coronavirus, which could put an end to the wave of lockdowns, deaths, and hospitalizations gripping our world. 

Most scientists agree that finding a safe, effective vaccine — as quickly as possible — is the only viable path out of the pandemic. But the number of people reassured by any future Covid-19 vaccine’s safety is dwindling. Only 50% of Americans would be willing to get injected with an FDA-approved vaccine, an October Gallup poll found, a worrying 11-point dip from last month. The numbers vary by country — while in China, 97% of people say they would take a vaccine, in parts of Europe the skepticism is on par with the U.S., with almost half of respondents in Poland and Hungary saying they would spurn the vaccine.

Among Facebook’s massive anti-vaccine groups, and in conspiracy forums on other online platforms such as Instagram, 4chan and Twitter, the same grievances are emerging over and over again: that the vaccine will be rushed into completion, and will therefore be dangerous.

“Vaccination has been a controversial issue for a long time, even for established vaccines with a wealth of scientific evidence supporting their efficacy and safety,” said Karen Douglas, a professor of social psychology at the University of Kent. “A brand new vaccine is bound to cause some concern, and many people will naturally want to wait to see how it works and if it is safe.”

Last week, U.S. presidential candidate Joe Biden said he would consider making a safe vaccine mandatory, but acknowledged that he wouldn’t necessarily be able to enforce such a decision. Mandatory vaccination is a topmost fear among conspiracy circles — but confusion and worry about the development of the Covid-19 vaccine has been seeping into the rest of society, too.

Here, we’ll address some of the most common concerns about the current Covid-19 vaccine trials. 

Some of the research for coronavirus vaccines had already been done before the pandemic. 

The laboratory that’s racing the fastest to find a vaccine is Oxford’s Jenner Institute. Part of the reason they’re ahead of the pack is because they have already developed vaccines for other viruses — including other coronaviruses – that are similar to the Covid-19 vaccine. 

“It’s sort of like having a half-baked recipe, and you just need to tweak it,” said Helen Bedford, a professor of children’s health at University College London who specializes in vaccine acceptance. “It’s just adapting the technology that’s being used for other vaccines to make it appropriate for coronavirus.” 

The Oxford researchers were also ahead of the curve because they had already tested their similar vaccine on humans, found it to be safe, so were able to start confidently testing their Covid-19 vaccine on large numbers of people much earlier.

Some trials’ phases are being stacked up, not skipped over. 

“There are a lot of really incredible people out there working night and day to develop the vaccine — because of the good it will do to the public,” said Helen Bedford. Scientists are not cutting corners, Bedford explained — “they wouldn’t be allowed to, the regulators would not approve it.”

Vaccine trials are generally carried out in three phases. The first phase usually sees tests on a small group of people — say, a few dozen — to find out if the vaccine is safe. During phase two, the shot is tested on different, often vulnerable age groups, such as the elderly and young, to find out if they respond well to the vaccine. The final part of the trial looks more broadly at how the vaccine works across a large group of thousands of people.

Once researchers are confident that a vaccine is safe, they may overlap each phase, rather than carry them out in sequence. This means that in an urgent situation like a pandemic, they can speed up the overall time taken to complete the trial, without compromising on safety. 

Some vaccines have already been manufactured, even though the trial hasn’t finished 

AstraZeneca, the drug company developing a Covid-19 vaccine in partnership with Oxford University, has already begun manufacturing its promised two billion doses of the potential vaccine, even though the trial hasn’t finished. This means that if the vaccine proves safe and effective, they will be able to start distributing shots straight away, speeding up the process significantly. AstraZeneca is taking a financial leap of faith here, because if the trial fails, all those manufactured doses will be destroyed. 

Drug companies are pouring huge resources into the race to find a vaccine

AstraZeneca claims the company is not going to make a profit from any Covid-19 vaccine. While it’s almost inevitable that drug companies and investors alike will profit from an eventual vaccine, vaccine advocates say that shouldn’t be a factor in trusting the product they come out with.

“Pharmaceutical companies — they do make zillions of pounds, but the proportion from vaccines is absolutely miniscule. It’s about two or three per cent, and it’s usually plowed back into development,” said Bedford. “Some people actually do these things for the benefit of mankind, not because they want to make a million quid.”

Two big vaccine trials have been paused – and that’s a reassuring thing.

Halting a vaccine trial is absolutely normal, and often happens during major studies involving human subjects. If a participant falls ill after receiving the vaccine, organizers pause to investigate why, and find out whether the participant’s illness is at all linked to the vaccine. This can take quite a while and is a standard feature of any vaccine trial. “They stopped; they looked at it in detail. That is part of the trial process, there’s a procedure in place to do these things,” said Bedford.

Two of the most prominent vaccine trials, carried out by AstraZeneca and Johnson & Johnson, have been put on pause over the past few months. AstraZeneca’s trial has now restarted, after the Oxford scientists deemed it unlikely the vaccine was linked to the participant’s symptoms.

“After independent review, these illnesses were either considered unlikely to be associated with the vaccine or there was insufficient evidence to say for certain that the illnesses were or were not related to the vaccine,” a document issued by the Jenner Institute said. This should be a reassuring thing: it means scientists are first and foremost concerned with making sure the vaccine isn’t harming people, and are continuing to closely monitor their symptoms as they move forward with their research.

Conspiracy theorists continue to churn out fake stories about the coronavirus vaccine. 

One of the latest is a false claim pushed by a Russian disinformation campaign that the vaccine will turn humans into monkeys. It’s a theory that harks back to the 1790s and the time of vaccine pioneer Edward Jenner, when rumors proliferated that the cowpox vaccine would turn people into cows.

Scientists have called for researchers to be more transparent about the coronavirus vaccine trial process to help bolster public confidence. But it isn’t always easy, as participant confidentiality is a key part of any research involving human subjects. 

Vaccine advocates are worried disinformation could crush eventual uptake of a coronavirus vaccine. “Having a vaccine available will not be enough to stop the pandemic if conspiracy theories go unchallenged,” said Douglas.