The government has said the decision by Johnson & Johnson to delay the supply of its Covid vaccine to Europe, while the US investigates reports of six cases of unusual blood clots in young women who have had the jab, will not derail the UK’s vaccination programme.

That reflects well on the decisions taken by the Vaccines Taskforce, originally headed by Kate Bingham.

The UK bought 30m doses of the J&J vaccine, along with 100m doses of the Oxford/AstraZeneca vaccine. But the taskforce spread its bets. As a result, any delays to the J&J order may not matter.

These two vaccines are both made with the same technology – the spike protein gene of the coronavirus is delivered via a vector, which in the case of J&J is a human common cold virus and, in the Oxford vaccine, a similar chimp virus.

Bingham and her team chose vaccines from four different technology “buckets”, as she called them.

In an interview with the Guardian last July she explained the thinking. She talked of two “hairy, scary, sexy ones” which were new and advanced technologies. The viral vector vaccines, like AZ and J&J, were one; the other was the mRNA vaccines, like Pfizer/BioNTech and Moderna.

The other two technologies she characterised as “the rather boring, much more established vaccine formats, which we know much more about, but they are further behind in clinical development”.

Those more tried and tested strategies included using the whole killed virus, which is how vaccines were traditionally made.

The Valneva vaccine is one of those. Although it is still in trials, the government demonstrated confidence in February by ordering 40m more doses, to total 100m, which is as big a contract as for AstraZeneca’s. The vaccine will be made in Scotland, which reduces supply issues, and should be available later in the year.

The fourth bucket is vaccines that use an adjuvant – to boost the immune system. GSK and Sanofi are trailing their vaccine designed in this way. They tweaked it after poor results and restarted trials in February.

When the taskforce was drawing up its shopping list, the key question was whether the vaccines would work at all.

It surprised everybody that so many of them had such excellent results in large-scale trials. Efficacy of 80% or 90% was hardly dreamed of in the early days – there was a general agreement that anything more than 50% effective against a brand-new virus would be amazing.

The blood clots with low platelets being investigated for links to the AstraZeneca and J&J vaccines are rare events – four in 1m for AZ in the UK, where more than 20m doses have been given, and around one in 1m for J&J in the US.

At that low rate, and with diagnosis and treatment improving, the risks are far outweighed by the deaths and damage from Covid-19.

It is unlikely there will be much of a glitch in supply as a result of the investigations, but if there is, the UK has other vaccines in the pipeline.

Unfortunately, in much of the world, where AZ and J&J are intended to be the mainstay of vaccination, that is not the case.

This content first appear on the guardian

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