Astrazeneca vaccine faces new setbacks
LONDON — Britain said on Wednesday that it would curb the use of Astrazeneca’s vaccine in adults under 30 because of the risk of rare blood clots, a blow to the efforts of scores of countries reliant on the vaccine to stamp out the coronavirus pandemic amid a global surge in cases.
Adding to the unease, the European Medicines Agency outlined a “possible link” between the vaccine and rare clots, even as it said that COVID-19 remained the far greater threat, leaving decisions about how to use the vaccine in the hands of the 27 member states of the European Union.
Taken together, the decisions represented a considerable setback for the Astrazeneca shot, which has been seen as the principal weapon in the battle to reduce deaths in the vaccinestarved global south.
The world’s most widely administered coronavirus vaccine, it is far less expensive and easier to store than some of the alternatives, spurring its use in at least 111 countries, rich and poor. Astrazeneca, based in Britain, has promised to deliver 3 billion doses this year, enough to inoculate nearly 1 in 5 people worldwide.
Britons under 30 will receive another vaccine if one is available, with limited exceptions, officials said. Until Wednesday, Britain had not wavered in its use of the homegrown vaccine, holding out even as many European neighbors paused injections over the unusual, though sometimes fatal clots.
But cases began to appear in Britain as well, and a consensus has since emerged among global regulators that the evidence points to a plausible link, as yet unexplained, between the vaccine and rare clots.
The concerns have arisen even though the clots are exceedingly rare. As of Sunday, officials said, European regulators had received reports of 169 clots in the brain and 53 other clotting events, often combined with low platelets, among roughly 34 million people who had received the Astrazeneca vaccine across Europe.
Britain has purchased enough vaccines from multiple makers that the policy change on Astrazeneca should not significantly slow the pace of inoculations. But other countries are starved for doses. Cameroon and Congo have already delayed injections of Astrazeneca’s vaccine amid mounting concerns in Europe. Any further hesitation, scientists said, could cost lives.
“In developing countries, the dynamic is to either use the vaccine you have, or you have nothing,” said Penny Ward, a visiting professor in pharmaceutical medicine at King’s College London. “In which case, carnage ensues.”
For the vast majority of people, British and European regulators said Wednesday, the benefits of Astrazeneca’s shot far outweigh the risks. The clotting problems were appearing at a rate of roughly 1 in 100,000 recipients across Europe. Meanwhile, in Britain, the vaccine has driven down hospitalizations from COVID-19 — which can, itself, cause serious clotting problems — and saved thousands of lives, regulators said.
British health officials estimated that the risk of being admitted to an intensive care unit for COVID-19 exceeded the dangers of the unusual blood clots in almost all age groups, and at almost every level of outbreak.
But because younger people are less likely to develop severe COVID-19, regulators said, any vaccine being given in that age group has to clear a higher safety bar. British data also suggest that younger people are more prone to the rare clots, making health officials there and in Europe warier about giving them the vaccine.
In response to the new regulatory guidance, Italy on Wednesday recommended not giving the Astrazeneca shot to people under 60. A number of countries, including Germany, France, Canada and the Netherlands, had already stopped using it in younger people, setting the age limit at 55 or 60. Norway and Denmark have put a total halt on the shot while they investigate.