CureVac flunks its coronavirus vaccine trial

Shares of CureVac plunged last night after the German biotech company announced disappointing results for its much-anticipated coronavirus vaccine. 

In late-stage trials, CureVac’s first-generation Covid jab was found to be just 47% effective – making it one of the least effective vaccines tested so far, and dampening hopes that it will play a key part in alleviating global vaccine shortages. 

The Nasdaq-listed company saw its shares fall by 50% in after-hours trading following the announcement. The results have caught scientists by surprise; not only is this vaccine candidate made from the same mRNA technology which has proven highly effective in the Pfizer and Moderna jabs, CureVac’s shots also displayed promising results in earlier clinical trials. 

CureVac’s vaccine was set to have some useful advantages over the other mRNA vaccines – its ability to keep stable for months in a standard refrigerator made it more suitable for distribution in poorer countries who desperately need more jabs. The flunked trial is also a big blow for the EU, which secured up to 405 million doses of CureVac in November. 

What is more, the news doesn’t bode well for an important deal sealed a few months ago in Britain: in late February: the UK government announced it was entering into a new partnership with CureVac to develop a second generation vaccine to target new virus variants. And it put in an initial order of 50 million doses in anticipation of this future jab. 

A Department for Health spokesperson insisted today that the government “remains committed to working with CureVac to develop a new vaccine which is effective against variants of COVID-19” – and CureVac says it will push ahead with plans to develop this second-generation vaccine, with a view to begin clinical testing on it in the third quarter of 2021. 

However, the weak trial results of its first generation vaccine undeniably casts doubt on the viability of this later project.  While the UK has set its sight on a version which would be tweaked to target variants, it would still be based upon CureVac’s existing -and fairly unpromising – jab. 

Of course, one crucial thing to decipher, is whether the disappointing results are down to the vaccine’s inability to create high levels of neutralising antibodies – in other words, a design flaw that existed all along-  or if they’re because of the high number of virus variants in the countries where the vaccine was tested. 

CureVac’s study was based on 40,000 people in Europe and Latin America and over half of the 134 Covid cases identified were caused by variants which have been shown to blunt vaccine efficacy. CureVac’s participants were infected with at least 13 different variants, some which are yet to be carefully studied. The Lambda variant, for instance, which has come to dominate Peru in recent weeks, accounted for 21 per cent of the samples.

If the poor trial results are not because of an inherent design flaw with the vaccine, but instead a result of recent virus mutations, then this study provides the biggest indication yet of the threat new variants pose to vaccine efficacy. 

CureVac’s result is undoubtedly a blow to morale. But there have been some other, more hopeful, vaccine developments in recent weeks. 

Earlier this week, a large study based in the US and Mexico, unveiled highly promising results for Novavax. The US drug-maker’s coronavirus vaccine was found to be 93% effective at preventing moderate to severe disease from the alpha, beta and gamma variants of the virus. (The delta variant, first identified in India, wasn’t circulating at the time of the trial). Novavax aren’t filing for regulatory approval until the third quarter of 2021 owing to difficulties sourcing certain raw materials for its jab. But it looks like a promising option for a booster later in the year – and the UK has already secured 60 million doses. The trial is also good news for COVAX, the UN-led initiative aimed at securing vaccines for poorer countries- who’ve signed an agreement with the biotech company for 1.1 billion doses. 

The government is also expecting deliveries of the newly-approved Johnson & Johnson jab “in the second half of this year”. It has ordered 20 million doses for the UK, and Jonathan Van-Tam, England’s deputy chief medical officer, says this single-shot vaccine could be a valuable option for hard-to-reach groups, where recalling them for a second jab is not always successful. 

Additionally, the Scottish-made Valneva jab is likely to be approved for use in time to act as an Autumn booster vaccine. If Valneva passes the final stage of its clinical trial, the UK is set to receive 60 million doses for the second half of 2021. 

This month, the UK has also launched its £19.3 million booster clinical trial, to decide which Covid jabs are the best candidates for any forthcoming autumn vaccination programme. Over 2800 people aged 30 and older are being recruited at 18 NHS sites from London to Glasgow, all of whom have already received two doses of AstraZeneca or Pfizer jab. In this ‘Cov-Boost’ trial, seven vaccines – Pfizer, AstraZeneca, Moderna, Novavax, Johnson & Johnson, Valneva and CureVac – are all being put to the test.