Last week’s announcement that AstraZeneca will no longer market its Covid vaccine brings an end to one of the century’s most remarkable medical stories. Created within a year of the pandemic’s arrival, the AZ vaccine was cheap, easy to store and transport, and helped avert humanitarian crises in Asia and Latin America, where many countries did not have the more expensive mRNA -vaccines could not afford what was snapped up. by rich western nations. It is estimated to have saved 6.3 million lives in 2021 alone.
Yet from the start the vaccine – created by research teams led by Professor Andy Pollard and Professor Sarah Gilbert at the Oxford Vaccine Center – has been dogged by controversy. It was linked to blood clotsAmerican observers have criticized protocols for its trials, and French President Emmanuel Macron has claimed they are “quasi-ineffective” for people over 65. In fact, the vaccine is particularly effective for the elderly.
In very rare cases, the AZ vaccine can cause blood clots. According to the British Heart Foundation, one study in the BMJ showed that for every 10 million people vaccinated with AstraZeneca there would be a total of 73 extra cases of blood clots. In contrast, 10 million Covid cases will cause thousands of extra blood clot cases.
Many of the concerns about the vaccine stemmed from national self-interest. Others, however, arise from the nature of vaccines themselves, and these bring issues that are likely to resurface with the arrival of any new pandemic in the coming years, scientists warned.
A vaccine is different from any other type of medicine because it works by stimulating a person’s anti-pathogen defenses, arming them against a future infection. However, this preparation goes beyond helping one individual and can help the general population, a point emphasized by Professor Stephen Evans of the London School of Medicine and Tropical Hygiene.
“If I’m on a preventive drug — like a statin — then I’m the only one who benefits,” Evans said. “However, there are people who cannot respond to a vaccine because they are sick or have a weakened immune system. They remain vulnerable. However, if you can build up herd immunity by ensuring that the maximum number of people are vaccinated, virus levels will drop and the vulnerable will be protected. If we believe we have responsibilities to help others, inoculated it is achieved. There are moral concerns about vaccination, in other words.”
Convincing the public – which has seen an increase in anti-vax propaganda in recent years – of this may not be easy. In addition, there is a second crucial difference between standard medical treatments and vaccines, added Professor Sir David Spiegelhalter of the University of Cambridge. “We never know the identities of those who benefit [from a vaccine] – they are ‘statistical’ people – while those who are disadvantaged can be named and their stories told.”
AstraZeneca’s Covid vaccine provides an example. We only know those who have been harmed by it, but cannot point out those who have benefited. Again, this makes it more difficult to establish a vaccine’s success and reassure people of its effectiveness. “To some extent, you can get around that and evaluate the impact of Covid vaccines by looking at the deaths of frontline health care workers during the early days of the pandemic,” Evans added. “Hundreds have died, but if we had a vaccine it is now clear that most would probably have survived.”
Most virologists and vaccine experts agree: if you look at the AstraZeneca vaccine from a global perspective, it has probably benefited tens of millions of people, prevented deaths and reduced the long-term consequences of Covid. It was a remarkable success, but its demise was marked by many emphasizing its side effects but never touching on its achievements.
“The paradox of vaccines is that people forget how important they are,” said Professor Adam Finn of the University of Bristol. “They are like democracy. You enjoy it for a while and then forget how important it is to preserve it. That’s a problem.”
to newsletter promotion
On the other hand, it is also clear that politicians and officials will have to be careful about the claims they make, added Fiona Fox, head of the Science Media Centre. “Public confidence in vaccines will come from open and honest communication. The benefits greatly outweigh the risks as with this vaccine.
“But you won’t win any arguments by claiming vaccines are 100% safe or running for the hills at the first reports of problems, which unfortunately too many government and NHS communications officers tend to do.
Reducing risks is always attractive when you need people to take a mostly safe vaccine, but it is ultimately self-defeating because it erodes trust in the longer term.”
