A group of nine vaccine developers has announced a “historic pledge” to uphold scientific and ethical standards in the search for a coronavirus vaccine.
The firms, including Pfizer and Merck, said they would only apply for regulatory approval after vaccines went through three phases of clinical study.
It comes amid global debates about the safety of vaccines made this year.
US President Donald Trump has said he wants one available in the US before November’s election.
No vaccine has yet completed clinical trials, leading some scientists to fear the search for a vaccine is being politicised and that public trust could be damaged.
In their pledge, the nine biopharmaceutical firms did not mention Mr Trump but said they believed their action would “ensure public confidence” in the development of any inoculation.
They pledged to “always make the safety and well-being of vaccinated individuals our top priority”.
Other signatories were industry giants Johnson & Johnson, BioNTech, GlaxoSmithKline, AstraZeneca, Moderna and Novavax.
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“Together, these nine companies have collectively developed more than 70 novel vaccines that have helped to eradicate some of the world’s most complex and deadly public health threats,” the statement added.
Nearly 180 vaccine candidates are being tested around the world, according to the World Health Organization (WHO).
China and Russia have begun inoculating some key workers with domestically developed vaccines.
Meanwhile the US national regulator, the Food and Drug Administration (FDA), has suggested that coronavirus vaccines may be approved before completing a third phase of clinical trials.
Last week it also emerged that the US Centers for Disease Control and Prevention had urged states to consider “waiving requirements” in order to be able to distribute a vaccine by 1 November – two days before the 3 November presidential election.
President Trump has hinted that a vaccine might be available before the election. But his Democratic rival Joe Biden has expressed scepticism that Mr Trump will listen to scientists and implement a transparent process.
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The WHO has said it does not expect a vaccine to be approved this year because of the time it takes to test them safely.
“This Phase 3 must take longer because you need to see how truly protective the vaccine is. You also need to see how safe it is,” said WHO spokeswoman Margaret Harris.