KIRAN STACEY: Once upon a time, Donald Trump

was a prominent vaccine sceptic, frequently telling

interviewers that he believed childhood vaccinations were

to blame for what he called an autism epidemic.

Well, now, with his re-election chances depending in part

on whether or not a coronavirus vaccine will be approved

in time for November's vote, the president

has changed his tune, instead calling out

his opponents for what he calls anti-vaccination rhetoric.

Meanwhile, those opponents, Joe Biden and Kamala Harris,

have been out there warning about the risks

that they see of rushing through a vaccine approval

before November's election.

Public health scientists are delighted that the president is

banging the drum for vaccines.

But they're worried that the way in which this is becoming

an election issue risks undermining confidence

not only in a coronavirus vaccine, but in vaccines

more generally.

A poll recently out by the Kaiser Family Foundation

found that over 50% of Americans say

they wouldn't take a coronavirus vaccine if it was approved

before November's election.

We don't know for sure how many people

need to take a vaccine for the coronavirus

to stop spreading through the community.

But we believe it is somewhere in the range of 60% to 70%.

Against this backdrop, the pharmaceutical companies

that make vaccines are beginning to get worried.

Caught between a president who is

desperate for some kind of pre-election boost

and his opponents, who are casting aspersions on the US

drug approvals process, they're worried that their reputations

might take a long-term hit.

So nine of them have come together

to put out a rare joint public statement,

saying that they won't push for approval of their vaccines

before they're confident that they

are both safe and effective.

The question is, are they willing

to hold off and stop Mr Trump getting

any kind of pre-election boost by not

submitting their plans for approval until after November?

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