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Explainer: The logistical challenges for the roll-out of a Covid-19 vaccine

The news yesterday was really positive, but there are practical considerations to bear in mind.

Image: PA

THE ANNOUNCEMENT FROM Pfizer and BioNTech yesterday that their Covid-19 vaccine was 90% effective in its large-scale Phase 3 trial was much needed positive news in the pandemic.

It has been hailed as a ‘watershed moment’ and welcomed by scientists, health officials and world leaders. However they have also cautioned people to recognise that yesterday’s announcement does not signal a swift end to the global pandemic.

What happens next will take time, money and a lot of planning – and the vaccine that is being developed by Pfizer and BioNTech may not even be the one most widely used across the world.

What do we know about the Pfizer/BioNTech vaccine?

The vaccine candidate is one of ten at the Phase 3 clinical stage, which involves tens of thousands of volunteers, some of whom will be given a placebo. At this phase, the developers are aiming to catch the less common side effects and to assess how effective it is across a diverse pool of people in terms of age, race and sex.

This vaccine uses molecules called ‘messenger RNA’ (mRNA) and is a vaccine approach that has never reached approval before.

Many traditional vaccines involve injecting people with a small amount of the virus. 

With this new approach, the immune system never has to be exposed to the actual virus. Instead, it makes human cells grow what is know as spike proteins, causing the immune system to produce antibodies against the virus. 

The scientific community has been very excited about this novel approach and one of the main positive takeaways from the news yesterday is that this experimental method of developing a vaccine, which is also being used by Moderna, appears to work well. 

The Pfizer/BioNTech Phase 3 study enrolled 43,538 participants, 42% of whom have ‘diverse backgrounds’, according to the companies. This included participants aged 65 to 85. It said no “serious safety concerns” have been observed. 

There have been 94 confirmed cases of Covid-19 in trial participants. 

Pfizer/BioNTech said the vaccine was found to be more than 90% effective in preventing Covid-19 in participants. 

Logistical challenges

The vaccine requires two doses. This means twice the number of visits to a vaccination centre – or wherever it is administered. At best this would result in resource and administrative challenges in first world countries, but it presents a much more serious barrier for less developed countries.

Another serious roadblock is the temperature at which this vaccine needs to be stored: at -80 degrees. 

For temperatures as cold as the Pfizer/BioNTech vaccination requires, dry ice has to be brought into the mix. Currently, the vaccine is shipped in coolers that can be fed with dry ice to keep it frozen for 15 days. After this it can be refrigerated for up to five days before being diluted and injected.

The medical community is already well familiar with the use of the ‘cold chain’ for vaccinations such as flu, but GPs and pharmacists, who play a significant role in the vaccination programme, do not have this kind of infrastructure.

Speaking to TheJournal.ie Dr Nuala O’Connor, Cork GP and Covid lead for the Irish College of General Practitioners (ICGP) said GPs “don’t have fridges that go down to minus 80″.

“The way it works through the national procurement system is we get a delivery every two weeks from the cold chain service. There are specialised vans that come with the vaccines. Now I don’t know whether the vans can do that temperature but we currently don’t have the capacity to store vaccines in our surgeries.

“If that were to become the main vaccine, there would obviously be a lot of logistics in rolling it out via GPs or pharmacies, it might all have to be done in specialised centres.” 

Infectious disease expert Professor Sam McConkey told RTÉ’s Today with Claire Byrne that, if it had to be done, getting a minus 80 degree fridge could be done “relatively easily” and those working in hospitals and laboratories use liquid nitrogen and dry ice regularly. 

However he said people will need training and personal protective equipment as there are risks associated with these substances. 

“I think that’s a surmountable hurdle in Ireland, I think it will be harder in developing countries,” he said.

“I’ve worked a lot in west Africa and their having a minus 80 [degree] freezer all over rural west Africa might be  more difficult. I see that as a technical challenge that could be met in Irish general practice if we needed to.”

Safety questions

With the fast development of all of these vaccines, there are understandable concerns about how safe they are.

Speaking last month to TheJournal.ie, Dr Fidelma Fitzpatrick, consultant and senior lecturer in microbiology at the Royal College of Surgeons (RCSI) said it normally takes between five to 10 years to bring a vaccine to market.

“There has never been a time when the entire world has been so focused on one type of vaccination programme so there will be huge scrutiny of the safety of these vaccines,” she said.

“The whole point of the Phase 3 trials is to find any rare side effects that wouldn’t come through in the Phase 1 and 2 trials.

“This isn’t going to get a free pass, there’s too much to lose, the entire world is looking at it so the regulators aren’t just going to push things through.”

Professor Sam McConkey said most products disappear quickly from the human body so the majority of side effects would happen soon after the product is taken. Pfizer and BioNTech have not released detailed data on any side effects associated with their vaccine, other than stating in their press release that no serious safety concerns have been observed.

“The thing that reassures me about safety is the 44,000 people, that’s quite a large number,” McConkey said. “Other products might be brought to market, for example, with 5,000 or 10,000 people who received it so it’s the size of the trial and the quality of the follow-up and the duration of the follow-up that really matters.”

Could we get the Pfizer/BioNTech vaccine in Ireland?

In total there are ten candidate vaccines at the Phase 3 clinical stage, with some like Moderna (also an mRNA vaccine) aiming to file for authorisation later this month.

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They will not all face the same logistical challenges as the Pfizer/BioNTech candidate. the Oxford/Aztrazeneca vaccine, for example, only requires one dose and does not have to be kept at such a low temperature. 

It’s possible the Pfizer/BioNTech vaccine will be one of the vaccines used in the European Union. Today European Commission President Ursula von der Leyen said the Commission will authorise a contract for up to 300 million doses of the BioNTech and Pfizer vaccine.

She described the vaccine as “the most promising so far”. 

The Commission has also reached agreements with three other companies that have a vaccine in development:

  • It agreed with AztraZeneca to purchase 300 million doses with an option to buy 100 million more.
  • It signed a contract to purchase up to 300 million doses of the Sanofi-GSK vaccine.
  • It approved a contract with Janssen Pharmaceutica NV to purchase 200 million vaccines with the possibility to purchase a further 200 million.

Von der Leyen said once the vaccine becomes available, the plan is to “deploy it quickly everywhere in Europe”. 

“This will be the fourth contract with a pharmaceutical company to buy vaccines. And more will come. Because we need to have a broad portfolio of vaccines based on different technologies,” she said.

“We have already started working with Member States to prepare national vaccination campaigns.

“We are almost there. In the meantime, let us be prudent, and stay safe.”

Even after the logistical challenges with vaccines are worked out, the mass production and distribution of the product will take time. It is likely the vaccination will first be given to healthcare workers and those in the most vulnerable categories, such as people with underlying conditions and those living in residential care homes. 

A significant proportion of the world’s population will have to be vaccinated – including those in less developed countries where there will be greater challenges – before countries can return to anything close to the normal we knew before the pandemic. 

Health officials and doctors have been quick to remind people the Pfizer/BioNTech data has not been published, peer reviewed or assessed by regulators and that a press release from the two companies does not mean public health measures can be abandoned.

Yesterday Chief Medical Officer Dr Tony Holohan pointed out that the Pfizer/BioNTech Phase 3 trial is not yet complete. 

“We’ve seen it [the press release] and we know there are a number of companies involved in vaccine development,” he said. “And we’re hopeful that we will see reliable data when it becomes available to the regulatory authorities, who have to inspect this data. When it’s published in the scientific literature and we’re in a position to examine it, then we’ll determine,” he said yesterday.

“But we’ve seen it and we’re aware of it and, obviously, if these are borne out when we see the regularity data, if these are borne out when we see these scientific publications, that’s the kind of thing we’ll want to be seeing.”

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