Next up on the vaccine news front are some concerns about efficacy. In a very surprising statement, Gao Fu (the head of the Chinese Center for Disease Control and Prevention) said at a conference in Chengdu over the weekend that that the protection figures of the Chinese vaccines are “not high”. He called for research into extra doses, changes in dosing schedules, mixing of different varieties of vaccine in those schedules, etc. This comes after news of countries like the UAE offering a third dose of the Sinopharm vaccine to some patients.
That said, the WHO has stated that the Sinopharm and Sinovac have both submitted data to show “levels of efficacy that would be compatible with those required”. But that, I believe, means that they at least clear the 50% efficacy floor – getting hard numbers on their actual protection has not been easy, though. Here’s a recent preprint from Brazil that estimates that efficacy in patients who received at least one dose of Coronavac (the Sinovac vaccine) against infection with any variant of the coronavirus came in at 50% for symptomatic infections. Chile is another country that has done a strong job in vaccinating its population, but largely with Sinovac, and there are questions about how well that’s working out. I think that even 50% efficacy is a lot better than nothing, but it’s possible that the Chilean results show how how such a vaccine can keep more people out of serious trouble (good) while still allowing for continued spread in the population (not good). The Chilean government says that they’ll be releasing more data on this soon, so we’ll come back to the topic.
Gao’s statement got a lot of headlines, and it appears that the Chinese government was not happy about it. Discussions about it seem to have been taken down on Chinese social media sites, and Gao himself issued a much less forthright statement hours later. The government has made much out of “vaccine diplomacy”, seeing a chance to raise China’s profile in many countries around the world, but right now, it’s not clear if that’s working out. That UAE story above, for example, mentions that Malaysia declined an offer of 500,000 doses of Sinopharm vaccine from the UAE stocks.
The “Sputnik-V” vaccine from the Gamaleya Institute has had far fewer questions about its efficacy than the Chinese candidates, although I haven’t seen much real-world data so far. Slovakian authorities, though, are saying that their deliveries of the vaccine seem to have come from a number of completely different production batches (with different dosage forms) and have questioned how the efficacy might change across these. In response, Russia has asked Slovakia to return their doses, due to “numerous contract violations”. India has just authorized the vaccine for emergency use there, with Dr. Reddy’s as the local supplier and more companies to come.
There’s a second Russian vaccine, EpiVacCorona, which is much less well known – Olga Dobrovidova writes about it here at Science. The only paper on it is in a small Russian journal, and describes a Phase 2 trial with 86 patients, without any estimate of efficacy. But there have been letters to the Russian health minister from people who had had this vaccine during trials and who have been tested with commercial antibody kits and found no coronavirus antibodies. EpiVacCorona is a protein-subunit vaccine, and the agency developing it says that it’s in a 3000-patient Phase 3 trial now.