‘We’re talking about a vaccine that has never been distributed in humans’

Matt Woodley

10/11/2020 7:14:54 PM

News of Pfizer/BioNTech’s COVID vaccine efficacy is ‘exciting’, but multiple Australian experts have told newsGP challenges lay ahead.

COVID vaccine vials
Pfizer/BioNTech’s candidate requires two doses, uses unproven technology, is in limited supply, and must be stored at -70°C. (Image: AAP)

Less than a week after Australia announced a supply deal to access 10 million vials of Pfizer/BioNTech’s coronavirus vaccine BNT162b2, new information has been released indicating the mRNA candidate is 90% effective.
Dr Anthony Fauci, the US Government’s top infectious-disease expert, described the results as ‘just extraordinary’ and said ‘not very many people’ expected it would be ‘as high as that’.
While promising, multiple Australian experts have told newsGP many challenges lay ahead – including logistical challenges related to transportation, storage and record-keeping.
Pfizer/BioNTech’s candidate requires two doses, uses unproven technology, is in limited supply, and must be stored at -70°C.
But most pressing, according to University of Sydney vaccine expert Professor Robert Booy, is confirming the vaccine is safe.
‘We do know that with respiratory virus vaccines in the past, there have been occasional, unwanted and severe side effects,’ he told newsGP.
‘We’re talking about a vaccine that has never been distributed in humans, and that is a vaccine made of messenger RNA – ribonucleic acid.
‘Before we even get to the almost presumptuous position of distribution, we really have to get final confirmation around safety.’
Professor Booy pointed out there has only been a median of around two months of follow up for this candidate, and authorities ‘still need to do the due diligence and the appropriate safety monitoring’ before widely distributing it to the public.
‘It’s so exciting to think that tens of millions of doses could be produced for routine use this year, and over a billion doses are slated to be introduced next year,’ he said. ‘[But] we just do not yet know if there are medium-to-long-term side effects.
‘It’s a little premature. Australia and other parts of the world are already manufacturing it on the basis that they’re expecting success – but it’s not guaranteed.
‘It’s not that I’m expecting a problem, but we do need to do the appropriate safety analysis over months rather than weeks.’
RACGP Victoria Chair Dr Cameron Loy shares the same hesitancy.
‘We need to be cautious not to jump on the hype train,’ he told newsGP. ‘The early data is based on a fairly small sample size.
‘It doesn’t mean it won’t work and it still is a likely candidate, but we all got excited about remdesivir [as well].’
Burnet Institute epidemiologist Professor Michael Toole likewise told newsGP there are many questions that need to be answered before a rollout begins.
‘There are still a few technical questions that Pfizer hasn’t answered,’ he said. ‘For example, is it just as effective in elderly people as it is in young people?
‘Does it stop transmission or does it only prevent progression to disease?
‘They’re very important questions to answer, because if it doesn’t stop transmission then we need to ensure other non-pharmaceutical precautions are still in place, as it will take a while to rollout, no matter the country.’
However, should the candidate eventually be distributed in Australia, Dr Loy believes GPs are well-placed to lead the rollout – cold chain issues notwithstanding.
‘The distribution of an ultra-cold vaccine [the Pfizer/BioNTech candidate must be stored at -70°C] is a lot more complicated than the distribution of the normal influenza vaccine or any other vaccine that general practices and, for that matter, even hospitals [generally facilitate],’ he said.
‘Having a cold chain that can maintain those temperatures all the way through the delivery is going to be a special and unique logistic challenge for the entire nation.
‘This is probably a vaccine cold chain that’s almost unachievable in many parts of the world. Even hospitals struggle to have refrigerators that can keep the vaccine at that temperature for long periods of time. So this is going to be a challenge.’

There are concerns BNT162b2’s sub-zero storage requirements will make distribution difficult.

Pfizer spokeswoman Kim Bencker told Reuters the company is working on a plan that includes the use of dry ice to transport frozen vaccine vials by air and land at their recommended temperatures for up to 10 days.
Should the plan come to fruition, it would allow the company to distribute the vaccine globally from its centres in the US, Germany and Belgium.
Ms Bencker added that the vaccine can be kept in an ultra-low temperature freezer for up to six months, or at 2–8°C for five days. However, previous analysis from scientists outside the company suggested it could only withstand those temperatures for 24 hours.
Keeping certain coronavirus vaccine candidates at sub-zero temperatures has been described by some as ‘the key’ to ending the pandemic, and while Dr Loy said it remains unclear how long the Pfizer/BioNTech candidate could survive outside of -70°C temperatures, similar progress has been made with other medications.
‘It does mean that we’re going to need a very detailed distribution pathway to get this out, and general practice is probably the only place that is going to be able to effectively deliver this consistently and continuously in the volumes that are required,’ he said.
‘General practices generally have a pretty good on-site cold chain that is monitored as part of the accreditation standards, which will keep things within a temperature range – but our vaccine fridges don’t go down to -70°C.
‘They’re available, but they’re expensive and they would require very specific handling protocols; -70°C is damn cold.
‘I don’t think that’s actually the way it’s going to end up being. I think there will be a period of time where the vaccine is permitted to be at a slightly lower temperature, that’s going to be a lot easier and safer to handle at the delivery point.’
Dr Loy also dismissed concerns the cold chain requirements would prevent rural and remote communities from being able to access this particular candidate.
‘If you’ve got the transport logistics, you’ve got the transport logistics. It will be able to be delivered into rural areas and it’s not reasonable for us to say “tough luck” because you live in a rural part of Australia,’ he said.
‘They freeze it at -70°C, then transport it on dry ice in either trucks or planes, and then it’s viable for some period of time before it gets delivered into the arms of recipients.
‘Now, that’s entirely practical. If Kalgoorlie can get lobster, I reckon they can probably get a vaccine.’
Another advantage of utilising general practices, Dr Loy said, is that it would help avoid people congregating at mass-vaccination sites and ensure quality record-keeping.
‘A midsize general practice would have access to a population of 5000–10,000 of the community,’ he said.
‘That’s a task that can be delivered over a period of time in a way that’s safe; it’s not going to overcrowd, it’s going to maintain social distance, and it’s going to be able to deliver the cold chain without having to create something new.
‘Importantly, general practice also has a proven track record of being able to upload the data, so that the Government knows how many people have been immunised and where they’ve been immunised.
‘General practice is one of the very few vocations that consistently and effectively uploads to the immunisation registry.’
Record keeping will be vital, according to Professor Toole, as the limited number of doses – Australia has only secured enough to immunise five million people – means any rollout will need to be highly targeted.
‘Clearly health workers first, everywhere, particularly in the cities,’ he said. ‘Then the elderly, people with underlying conditions, and then the general population.
‘Logistics, planning and record-keeping are going to be the big challenges. The other unknown is that we don’t know how long immunity will last.
‘There are lots of concerns, but the 90% efficacy is fantastic. It’s almost as good measles.’
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Dr Primo Phillip Bentivegna   11/11/2020 12:24:16 PM

Let me guess, GP practices will be expected to purchase their owm sub-freezing fridges!

A.Prof Christopher David Hogan   11/11/2020 12:52:51 PM

Caution is good.
I was an investigator for several Australian drug trials & value caution because of that.
We knew always from the start a vaccine would be problematic.
Do we have a choice except to test it on humans?
Well the only certainties in modern life are death, taxes & paperwork !