RIO DE JANEIRO, BRAZIL – Fiocruz infectologist Marcus Lacerda attends to at least 40 cases of Covid-19 in Manaus, capital city of the Brazilian Amazonas state, every day and is surprised that, unlike the first wave in early 2020, this time whole families have contracted the disease. He believes the emergence of a new strain of the coronavirus may be partly responsible.
The expert explains that the capital of Amazonas was severely affected last year due to its condensed profile, and by the pathogen’s entry into the state through overseas flights at the start of the respiratory virus season in the Northern Region. For Lacerda, it is very likely that the scenario will be repeated in the second wave and will further worsen with the combination of the delay in vaccination and the absence of properly implemented restrictive measures, such as lockdowns.
A scientist renowned for his pioneering work in infectious diseases, Lacerda is one of the most experienced infectologists in Amazonas and is at the forefront of the fight against Covid-19. He believes that Manaus is not an isolated case.
Why is Manaus experiencing this surge of the disease now?
Manaus was also the first to experience chaos in the first wave. The coronavirus follows the pattern of seasonal respiratory viruses. Influenza always starts here and then heads down, the South is always last. But this chaos we are experiencing here will spread (nationwide) unless vaccines come and properly executed lockdowns are in place. Manaus is neither an exception nor that different, and it is not (that much) worse than the rest of the country. The city is indeed a warning of what will happen to the rest of Brazil unless mass vaccination starts immediately.
Why did Covid-19 explode first in Manaus last year?
The city is very dense, the viruses come in by plane from abroad and we also had the coinciding arrival of the Sars-CoV-2 with the start of the respiratory virus season in the North Region, which happens during the rainy season. Manaus has outbreaks of influenza before the rest of Brazil every year. The coronavirus followed this course and everything leads to believe that the same thing will happen in this second wave.
What drove this second wave so strongly?
There are several factors. The poorly handled lockdowns, the population’s low adherence to social distancing and the wearing of masks are among the reasons and these are repeated in the rest of the country too. But it’s not only that.
And what else?
The emergence of a new strain of Sars-CoV-2 which is apparently more contagious and also manages to escape the attack of antibodies when it is not very powerful. These are still only clues, nothing has been proven.
What strain is this?
Everyone is talking about the Japanese (who returned from the city to the Asian country carrying the virus), but we sequenced 11 samples here and six of them had two mutations. These mutations are the E484K and the N501Y. Both affect the most fundamental part of the S protein. In turn, this is the most important part of the virus and target of vaccines and antibodies. The first one has already been found in other parts of Brazil, as in Rio de Janeiro, and the second was first seen in South Africa.
Where would this strain have come from?
Most likely from nowhere. It emerged independently here. Viruses mutate all the time and try to adapt. The most transmissible and which escape antibodies, obviously, have the advantage. So viruses that have mutations with these features are naturally selected and become dominant. And, therefore, mutations with these features may emerge and establish themselves independently in several places.
What would this spread be like in Manaus?
Perhaps this strain is already predominant and is responsible for over 50% of infection cases in Manaus. It is not yet predominant in the rest of the country, but it could be a matter of time.
Could this strain have already spread to other parts of the country?
Probably. When we see these many cases of the disease, it is because the virus has already spread for longer. And this strain, apparently, escapes from antibodies if they are not very powerful and it is also more contagious. We see whole families infected, sick, even the youngest. This did not happen in the first wave, when you had one or two cases within the same family, in general. Now it is common for the whole family to be infected. But these are still only clues. However, seeing patients every day, we have the feeling that the mutations are spreading.
How?
With asymptomatic people or with few symptoms. It is not patients who spread Covid-19. They are the easiest to maintain proper care to prevent transmission.
Can Manaus be experiencing mass reinfections?
Yes, there is a strong likelihood. Manaus had a high level of exposure to the coronavirus early in the year. It is believed that over 60% of the population has been exposed to the coronavirus. These people, who had mild symptoms of Covid-19 or did not even develop any symptoms, may have developed some antibody response, but it is either gone or too weak to fight a new strain.
Do you have proven cases of reinfection?
It is very difficult to prove a reinfection because you need to have samples of the first and second event and sequence them. We have one (single) proven case of reinfection, but there should be many more. The case is of a woman who had IgG antibodies for the coronavirus and still became sick with Covid-19 again. Her antibodies failed to stop the coronavirus. (The Ministry of Health confirmed on Friday, after the interview, a case of re-infection by the new variant in Manaus)
Are reinfection cases more serious?
We can’t say that yet. I see, on average, 40 people a day and the disease does not seem to be more serious. What makes the emergence of a more contagious strain more serious is the fact that more people get sick at the same time and place tremendous pressure on the healthcare system, which collapses. It is not that the disease has become more serious.
What needs to be done?
There is a lot we don’t know about new mutations, about the coronavirus. But it is certain that at this time social isolation needs to be intense and vaccination is urgent. We don’t have another option.