Thanks to vaccines, many countries have ended protective measures against covid-19 without a large increase in deaths. Nevertheless, just under one-third of people globally hadn鈥檛 received a single dose of covid-19 vaccine as of mid-December 2022, according to Our World in Data. Plus, immunity is waning and the SARS-CoV-2 coronavirus is evolving to dodge our immune systems.
We will therefore need new and improved covid-19 vaccines for many years to come. What can we expect in 2023? The disappointing answer is we will probably have the same vaccines, but fewer doses.
According to UK science analytics company Airfinity, the number of covid-19 vaccine doses sold globally fell from 5.7 billion in 2021 to 3 billion in 2022 鈥� and will fall further to 1.6 billion doses in 2023, probably because countries think the pandemic is less urgent.
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These figures don鈥檛 include nations producing their own vaccines, such as China, which hopes to ramp up its efforts. At the end of November 2022, China announced plans to vaccinate more of its older population. According to China鈥檚 National Health Commission, 40 per cent of people aged over 80 in the country had received three covid-19 vaccine doses in November, up from about 20 per cent in April.
Outside China, the mRNA vaccines produced by Pfizer/BioNTech and Moderna are likely to continue to dominate sales. Their latest vaccines code for the outer spike proteins of the original virus and two omicron subvariants.
鈥淭here is a possibility that the vaccines are updated again and, if that were the case, we鈥檇 expect it to be for the following booster campaign in autumn/winter next year,鈥� says at Airfinity. 鈥淏ut this depends on how the variants evolve over time.鈥�
There are 50 approved covid-19 vaccines, according to records compiled by McGill University in Montreal, Canada, though many are approved in just one country. Another 250 vaccine candidates are being tested in 80 countries.
Many of these candidates are similar to existing vaccines, but some groups are trying to develop vaccines that are better than the ones we already have.
One approach is to provide broad protection against a range of potential variants, making it harder for the virus to evolve to dodge vaccine-induced immunity. Pfizer is testing an mRNA vaccine designed to provoke a response by T-cells of the immune system against several coronavirus proteins, not just an antibody response against the spike protein. T-cells often provide longer protection than antibodies. Several of these vaccines are in development, but it is unlikely that any will be approved in 2023.
The second approach is to create vaccines that provide much better protection against infection and transmission by inducing so-called mucosal immunity.
The mucous membranes of our nose, throat and lungs are where infections typically start and where the viruses that go on to infect people are produced. The hope is that delivering vaccines directly to these membranes 鈥� such as via the nose 鈥� will stimulate a strong response.
Four nasal vaccines have been approved in China, India, Iran and Russia. There is little information on the last two, but India鈥檚 iNCOVACC and China鈥檚 Convidecia Air were approved on the basis that, when given as a booster, they produce levels of antibodies that are at least as high as those from an injected booster.
at the University of Oxford and his colleagues tested a nasal spray vaccine earlier in 2022, with disappointing results. As this was very similar to iNCOVACC, the team is trying to figure out why the candidate didn鈥檛 work as well, he says.
No nasal vaccines are likely to be approved soon in Europe or North America, says Douglas. Regulators will want to be sure they are safe and don鈥檛 cause an inflammatory response, for instance in those with asthma. Getting approval for any new vaccine is becoming harder, as they must be better than the ones we have, he says.
The need for new vaccines is also less urgent now, so candidates will follow the standard, longer time frames for approval, says Linley.
Overall, there is a way to go before we have a covid-19 vaccine that gives robust protection against infection, transmission and new variants, but we mustn鈥檛 take our eye off this goal, says Douglas. 鈥淭his is important not just for this pandemic, but to put us in a better position next time there鈥檚 a [new infectious] outbreak.鈥�
