ONEAt the beginning of the pandemic, it was very difficult to predict anything. There were forecasts of Covid-19’s endless pain, wave after wave of illness and death, and fears that we would be stuck in painful negotiations between our health and our livelihood for years to come.
But vaccines have changed everything. The light at the end of the tunnel is now much closer than we might expect in March 2020.
Few people would have – could have predicted the speed with which we developed vaccines. If you asked most scientific professionals what the realistic timetable for launching effective vaccines was, most responses would have stretched for years. And that was an understandable assumption – before Covid-19, the development of the fastest vaccination took four years, and many vaccines took much longer than that.
Covid-19 was first sequenced on January 10, 2020. The first Covid-19 vaccination not as part of a clinical trial was given on December 8, 2020 in the United Kingdom. 333 days in total to go from the most basic science to an effective and safe vaccination that is already saving lives around the world.
It really is a scientific miracle.
But with this miraculous success came a series of arguments. Should we choose the most clinically effective vaccine that most blocks transmission? What about herd immunity – which vaccine will give us the most protection in the long run?
To some extent, these discussions are important. Despite the initial stage of the worldwide vaccine launch, there is some evidence that certain vaccines have been shown to be more effective in the short term against the initial virus and its variants. If our goal is to prevent Australia from having any disease outbreaks, as we did very well with our Covid-19 restrictions, there is a reasonable debate to be made about which vaccine we want to use.
But it is also easy to lose the forest because of the trees. Even the least effective vaccine available seems to reduce the risk of the things we care about most – hospitalization and death – by a very large amount. Although individual tests were not developed to detect a statistically significant effect, the overall impact of vaccines appears to be that they reduce the risk of becoming really sick because of Covid-19, even if they do not prevent you from getting the disease entirely.
In addition, collective immunity is not an infallible bet, regardless of the vaccine. We can deal with variants in the short term, perhaps, but when we consider the term really long, things become inherently uncertain. If a vaccination prevents transmission for 24 months, but the protection decreases and then disappears entirely over a decade – similar, for example, to the pertussis vaccine – then collective immunity would be much more difficult to maintain. We may be in a situation where, similar to the flu, we all have to be vaccinated every year, except that, instead of being a public health bonus, it is a national need because otherwise the virus will spread again in the community.
Given that it is unlikely that the disease will be eliminated in much of the world anytime soon, we have to deal with the undesirable fact that people will be bringing the coronavirus to the country in the near future. SARS-CoV-2 will continue to mutate and, as I said at the beginning, making predictions is a kind of fool’s game.
With all that said, we can deal with what we know now, and what we know now is that all approved vaccines are safe and effective. Yes, there is some debate about whether, from a public health standpoint, the long-term benefits of one immunization over another are important. I’m not trying to drown out this conversation – it’s a discussion that we need to have.
But we must take a moment and consider where we were in February 2020 and how far we have come since then. We may have to live with Covid-19 for some time, but even the least effective vaccine approved so far is a level of success that no one predicted a year ago.
In Australia, two vaccines have already been approved by the Therapeutic Goods Administration: the Pfizer vaccine, which has a 95% efficacy rate after two doses, and the Astra Zeneca vaccine, approved on Tuesday, which has an efficacy rate of 62 %. A third vaccine, Novavax, 89% effective in phase 3 trials, was purchased in advance by the federal government, but has not yet been approved for use in Australia.
So, what vaccine will I get, as an epidemiologist and public health agent? Well, I fully agree with the Nobel winner Professor Peter Doherty in this: I will accept whatever is offered (and I will be happy to have it).
The best vaccine is the one in your arm.
• Gideon Meyerowitz-Katz is an epidemiologist who works with chronic diseases