17/08/2021

Speaking to Globo, Adam Kucharski says the vaccine will not contain Delta.

Foto: Ryan Lash / TED

In an interview with Globo published this Tuesday (17) and conducted during his participation in the 3Tuesdays Brazilian Mathematics Colloquium (CBM), British epidemiologist Adam Kucharski warned that the Delta variant of the coronavirus will be a watershed moment in countries' distancing policies. “Vaccination alone probably cannot stop Delta. And this leads countries to a big choice: whether they decide to suspend restrictive measures and assume that there will be some transmission or whether they will simply keep the measures in place,” he stressed to the newspaper.

The impact of the unequal distribution of vaccines on ending the pandemic was another topic addressed by Kucharski in the conversation. “We are seeing a large disparity between countries. And it’s truly shocking that we may end up having more deaths after the vaccine is invented than before,” commented the researcher. “It worries me that we have many countries in the world that are still under the threat of these catastrophes. This prolongs the epidemic and gives the virus an incentive to adapt and spread, through variants, including among vaccinated populations,” he added.

The interview was granted exclusively to the newspaper, immediately after the lecture by the professor from the London School of Hygiene & Tropical Medicine at the CBM, held virtually between August Mondays and Fridays. In his plenary session at the Brazilian Mathematics Colloquium, Kucharski spoke about how mathematics has been a fundamental tool in the fight to control Covid-19 .

Read the full article from Globo:

'Vaccination alone will not be able to contain Delta', says British epidemiologist.

British expert draws attention to the unequal distribution of doses among countries, which could lead the world to register 'more deaths after the vaccine was invented than before'.

Giuliana de Toledo

17/08/2021

SÃO PAULO — A kind of iron curtain is about to be erected in the world, and the one responsible for this segregation is the Delta variant of the coronavirus. For the British mathematician and epidemiologist Adam Kucharski, who has become a reference in analyses of the course of the pandemic, the planet will now experience a division between countries. On one side, those who want to resume a more normal life and, as a side effect, live with Covid outbreaks. On the other, those who, faced with the risks of the new strain, will leave the restrictive measures in place for longer, even for years.

— Vaccination alone probably won't stop Delta. And this leads countries to a big choice: whether they decide to lift restrictive measures and assume there will be some transmission, or whether they simply maintain the measures in place — summarizes the professor at the London School of Hygiene & Tropical Medicine and author of the bestseller "The Rules of Contagion: Why Things Spread — and Why They Stop Spreading".

According to Kucharski, the unequal distribution of doses among nations could lead us to register "more deaths after the vaccine is invented than before." He was a guest speaker at the 3Tuesdays Brazilian Mathematics Colloquium, held online by the Institute of Pure and Applied Mathematics (IMPA). After his participation last Thursday, the Briton spoke exclusively with O GLOBO.

What can mathematical models predict for the near future? On one hand, we have vaccines, but on the other, there is the Delta variant.

I think the models were quite optimistic a few months ago because the vaccines seemed to be doing very well and managed to reduce transmission enough before Delta arrived. But Delta raised the bar for what countries need to do. We are in a situation where vaccination alone probably won't be able to stop Delta, even if you vaccinate at very high levels. And this leads countries to a big choice now: whether they decide that the restrictive measures are unsustainable, that they want to lift them and that there will be some transmission because the vaccines can't stop it, or whether they will simply keep the measures in place. Especially some countries that haven't had many infections so far, and haven't developed much immunity (through contact with the virus), may want to keep some control measures in place for a few more years. We may see a major division of the world between these two different approaches.

In September 2020, when your book was published in Brazil, you said in an interview with GLOBO that you believed our routines would still be affected by Covid-19 for another year or two. How do you view that prediction today?

That was before the vaccines came along. And the vaccines that have appeared are better than we could have imagined, both in terms of effectiveness and the number (of options). But the problem is that the vaccines are being distributed unevenly. We are seeing a huge disparity between countries. And it's truly shocking that we may end up having more deaths after the vaccine is invented than before. This is something that probably few people would have imagined back then if they knew how good these vaccines would be.

Could the uneven distribution of vaccines significantly delay the end of the pandemic?

Yes. We're at a point where everyone in at-risk groups and all healthcare professionals worldwide could already be vaccinated. And, due to a series of choices made by countries, this hasn't happened yet. The virus can cause devastating outbreaks in certain areas, but once you reach a high level of vaccination, that doesn't happen anymore. You still live with the disease, it still causes problems, but it's not catastrophic. What worries me is that we have many countries in the world that are still under the threat of these catastrophes. This prolongs the epidemic and gives the virus an incentive to adapt and spread, through variants, including among vaccinated populations.

There is still, especially in rich countries, a refusal by part of the population to get vaccinated.

I think we need to separate people who just want health information and have reasonable questions. People who have health problems, pregnant women for example, who just want to receive information, and that's totally understandable. But there are also some well-organized efforts to undermine vaccines. And some of the things that some countries have said don't help either… If that happens, the epidemic could become much longer. If a particular country has very low vaccination coverage, a devastating epidemic can still happen. And that will lead governments to keep the measures in place. It's like having a door through which you can exit the pandemic, but there are people who don't want to go through it, and so we end up locked inside a lockdown scenario.

In Brazil, the Gamma variant still dominates, but the Delta variant is gaining ground. Regarding vaccination, we are making progress, but the percentage of the population fully immunized is still not high. Amidst this situation, São Paulo and Rio de Janeiro are planning to reopen their economies in the coming weeks. Does this seem advisable?

It will be difficult for many countries because they cannot maintain restrictions forever. Countries need to find a way back to normality, because you can't spend years and years with everything closed. But when vaccination coverage is low, you need to be flexible in decision-making, because we've already seen that Delta can enter very quickly even in countries with quite high coverage, like the UK and the US. Countries need to keep an eye on the situation and be prepared to change course if there are signs that it's too early to reopen.

The virus variants have become increasingly difficult to combat. Is there a real chance that we will soon be suffering from a new and worse strain?

I don't think so, based on what we see with seasonal coronaviruses and other viruses, like the flu. Over time, there's an incentive for the virus to evolve, but not necessarily to become inherently more transmissible. If it manages to escape immune responses, even if it's causing mild infections, that's already an advantage for it. For me, the question is: when will this evolution happen? Because the Delta variant is quite old now. Beta and Gamma too. Is the virus one step away from mutating, or is Delta really the ideal type of virus for the moment? We see this quite a bit with the flu. The virus experiments with different combinations and, in some of them, it's not very successful. We need to plan for this, with updates to vaccines and virus tracking.

During the pandemic, the general population is experiencing science in an unprecedented way. You've said in interviews with the British press that it's funny that even the tabloids have approached you to talk about concepts like "transmission rate." At the end of the pandemic, do you believe the population will have more confidence in science?

I hope so. (The pandemic) gave people a kind of insider's perspective (laughs). I think there are many parts of science that don't work very well. There are egos, there are inefficiencies, people make mistakes… I think some people saw for the first time how this system works. We, the scientists, need to think about why some of these problems happened. There are still situations where people are expressing opinions loudly without much evidence, or that go against the evidence we actually have. And that just creates confusion in the media and discussions about things we shouldn't even be discussing.