Vaccines offer hope, but the route back to a normal life is far from straightforward –

If – and it’s a big if – everything goes to plan it is plausible that all those most vulnerable to Covid in the UK could be inoculated against it by the end of April, say officials.

Richard Hatchett, chief executive of the Coalition for Epidemic Preparedness Innovations (Cepi), says the benefit of protecting the vulnerable with a vaccine should not be underestimated, in either human or economic terms.

“It would remove the biggest threat – of health services being overwhelmed”, he said. “It would allow social distancing measures to be relaxed and a gradual return to normal”.

Licencing may not be straightforward

For the next few days, probably weeks, all eyes will be on the regulators. Pfizer handed over its trial data to the US Food and Drug Administration (FDA) on Friday. The same information will be sent to the European Medicines Agency (EMA) in Amsterdam and the Medicines and Healthcare products Regulatory Agency (MHRA) in London very shortly.

Publicly, most experts are bullish on this process, perhaps conscious of fueling vaccine hesitancy if they air doubts. Others, however, say it would be wise to anticipate surprises.

All the limited phase three trial data published to date has been distributed by press release and regulators – always conscious of confirmation bias – will want to go through it with a tooth comb. They will have in the back of their minds unforeseen problems with previous vaccines that were licenced in a hurry, notably the 1976 US swine flu vaccine.

Did the five per cent who caught Covid after having the Pfizer and Moderna shots, all cluster towards the end of the trial period, suggesting its protection fades quickly? Was efficacy in older groups spread evenly between those aged 65 to 85 and is there data enough to know? Were side effects better tolerated by some than others? Is two months safety data enough for an mRNA vaccine that has never been used before? How safe are the manufacturing processes?

These are just some of the many vital questions regulators will ask.

It is also unclear if, and how, the FDA, EMA and MHRA will cooperate in their decision making. Two months ago the MRHA cleared the Oxford vaccine trial to continue after a serious adverse event was reported but the FDA dug its heels in and paused the US wing of the trial for more than a month.

It was not a good look and if stark differences emerge between regulators on licencing of the new vaccines public trust could take a serious hit.

Nick Jackson, head of programmes and innovative technology at Cepi, said medicines regulators had “strived to coordinate” from the start of the pandemic. However, he added that they may still come to different conclusions because “each must make their own risk-benefit assessment”. Nuances between countries such as health care capacity, age profiles and the incidence of co-morbidities will all influence each regulator’s final judgment.

Supply issues could stop a quick rollout

If and when the vaccines are given approval, supply issues could also prove tricky. The government has struck deals to secure 355 million doses of seven vaccines to date but the contracts are not publicly available and delivery times remain horribly vague.

For example, 10 million doses of the Pfizer vaccine – enough for five million people – are said to be “expected” before Christmas but the delivery date on the remaining 30 million ordered is “some time next year”. 

On the supply side, experts say much hangs on the trial results of the Oxford AstraZeneca jab, which are not yet known to anyone, including the Oxford team. 

Only four million doses of this vaccine have so far been delivered but as a home grown product, the UK is at the front of the queue for the first 100 million vials. It is also easier to manufacture and distribute as similar products have been made in the past and it does not need to be supercooled.