Analysis: Vaccination without lockdown could turn Brazil into a super-powerful strain “factory”

RIO DE JANEIRO, BRAZIL – British researchers point out that large-scale contact between vaccinees and the Manaus variant may produce mutations capable of completely evading vaccine efficacy.

The current scenario in Brazil, which combines the start of vaccination with uncontrolled Covid-19 transmission, may turn the country into a “factory” of strains potentially able to completely evade the vaccines’ efficacy. This is the assessment of British scientists directly involved in some of the leading studies on coronavirus mutations.

Researchers from Imperial College London and the University of Leicester argue that lockdowns and other containment measures are of particular relevance during the vaccination process of a population.

They explain that it is exactly the contact between vaccinees and variants that enables the emergence of “super-poweful” mutations, capable of completely evading the action of an immunizer.

And, in Brazil, there is an explosive combination for this to occur: vaccination is still sluggish, the E484k variant mutation (which evades antibodies) and high infection rates.

Manaus strain may favor antivaccine mutation

The greatest danger lies in the contact of the Manaus variant, nicknamed P.1, with recently vaccinated individuals, explains virologist Julian Tang, from the University of Leicester, UK.

According to him, by entering the human cell and facing a still small amount of antibodies from the vaccine, when the variant replicates, it can foster mutations that are more resistant to those antibodies.

“If you are vaccinated on a Monday, you are not immediately protected. It takes a few weeks for the vaccine antibodies to emerge, and you could still be infected by the original virus or the P.1 variant,” Tang explains.

“If these vaccine antibodies emerge while the infection is occurring and replicating in the body, the virus can replicate in such a way as to evade the antibody that is being produced, in a natural selection move.”

This is part of the evolutionary process of a virus, which tries to adjust to “adversity.” A vaccinated but infected individual can pass the mutated virus on if there are no control measures in place, such as quarantines, closure of businesses and recreational venues.

The risk of this occurring would be lower if the Manaus variant were not spreading across the country and if infections were under control. This is because the chance of the original virus being able to attach itself in large quantities to the cells of a vaccinated individual is slim, given that immunizers have been produced precisely to prevent this attachment from being effective.

But the E484k mutation, present in the Manaus variant, affects precisely the main point of attachment between the virus and the cells, rendering the “attachment” more effective and reducing the efficacy of the so-called neutralizing antibodies.

Preliminary research suggests reduced efficacy of the Oxford-AstraZeneca vaccine against variants with the E484K mutation, and the Butatan Institute is currently studying the impact on the CoronaVac’s protection percentage.

“If there is uncontrolled replication of the virus, i.e. transmission in an environment with no social distancing, lockdown and mask wearing rules, susceptible people will mingle with vaccinated individuals. Unhindered, the virus can spread among populations, potentially producing variants that evade the vaccine,” Tang said.

Peter Baker, Professor of Global Health at Imperial College London, also says that large-scale contact of coronavirus variants with vaccinated individuals generates biological “pressure” for these variants to evolve, thereby creating mutations that better evade antibodies.

“This will particularly occur in a large epidemic situation in a country with a moderate vaccination success. The perfect balance between immune and infected individuals is thus achieved. And when these populations mingle, there is a risk of a new vaccine-resistant variant emerging,” he said.

Uncontrolled epidemic in Brazil

Brazil experiences exactly this confluence between early stage vaccination and peak cases of covid-19. The country surpassed the United States in the unfortunate record of infections in 24 hours.

Data published on Thursday, February 24th,  by the World Health Organization show that 59,900 cases of covid-19 were recorded in Brazil within 24 hours. In the USA, there were 57,800.

The number of daily deaths also keeps rising and breaking records. On Wednesday, March 3rd, 1,900 deaths were registered in one day – the highest number since the beginning of the pandemic. In more than half of all Brazilian states, the occupation of ICU beds exceeds 80%.

Faced with the collapse of the health systems in many municipalities, governors have decreed lockdown or social distancing measures. Despite the uncontrolled infections, President Jair Bolsonaro has once again declared himself against the restrictions.

“As far as I’m concerned we will never have lockdown. Never, a policy that has not worked anywhere in the world,” stated the president.

But the data belie Bolsonaro’s statement.

In the UK, the lockdown in force throughout the country since the beginning of January has reduced by two thirds the infections by Covid-19. In London the decrease was 80%, according to research by Imperial College London.

“From a scientific point of view, closing borders and implementing home quarantines are effective in reducing infections. And there are benefits to reducing infections. You decrease the risk of variants emerging, you buy time for the vaccination campaign to progress, and for research to complete vaccines adapted to the variants that exist today,” says Professor Peter Baker.

Manaus strain could be dominant in the country

In addition, experts caution that without control measures, the Manaus strain could eventually replace the original virus and become dominant nationwide. The P.1 is already in circulation in at least 10 Brazilian states, in addition to being responsible for virtually all current infections in the capital of Amazonas.

“Without control measures, the P1 will quickly become the dominant virus and produce significant epidemic waves,” said Charlie Whittaker, a researcher at Imperial College London.

A study led by Whittaker showed that the Manaus variant is between 1.4 and 2.2 times more transmissible than the original virus. The research also reveals that P.1 is able to evade the immune system from previous infections in 25% to 61% of cases. In other words, it can cause reinfections in individuals who have already been infected by covid-19.

And reinfections are another important ingredient for dangerous mutations, says Peter Baker, of Imperial College London.

“When these variants come into contact with individuals who have already been infected, there is pressure for them to mutate further, to find a way to reinfect previously immunized people,” he says.

“The combination of a previous outbreak and a new major outbreak, where people who would already be immune are reinfected, creates a prone environment for mutations. We think that’s what happened in the Brazilian context.”

Emergence of variants in Brazil poses risk to the whole world

In addition to its spread throughout the Brazilian territory, the Manaus variant has already been detected in 25 countries, despite the fact that several nations have canceled flights to Brazil and imposed quarantines and Covid-19 tests on anyone landing from the country.

This shows that an uncontrolled disease in one country endangers other nations. “If Brazil is allowed to replicate the virus in an uncontrolled way, these variants can emerge and travel anywhere,” says virologist Julian Tang of the University of Leicester.

“If you have a virus production hotbed in a given country, unless you control transmission, you’re going to have mutations occurring by natural selection, if such variants travel around the world and some of them completely or partially evade vaccines, of course it’s a risk.”

The researchers assess that mass vaccination combined with measures to restrict social contact, such as lockdowns, wearing masks and closing down businesses are important to contain high rates of infections and prevent new mutations while immunization progresses.

“No one is safe until we are all safe. And ensuring we are safe means limiting the chance of variants emerging. Control measures are helpful in achieving this, but perhaps even more important is ensuring an equitable global vaccination strategy. That means no country should be left behind,” argues Charlie Whittaker of Imperial College London.

Source: BBC Brasil

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