The study was conducted by a British-Brazilian research team of researchers from institutions including Oxford University, Imperial College London and the University of São Paulo. The study found that the P.1 variant was 1.4 to 2.2 times more infectious than other variants prevalent in Brazil.
The researchers found that the P.1 variant also “evades 25 to 61 percent of the protective immunity that the body has from prior infection with any earlier variant,” an indication that current vaccines may also be less effective against it.
International concern about the P.1 variant has recently escalated. The variant has now been found in more than 25 countries, including Belgium, Sweden and the United Kingdom, where six cases have been identified.
Scientists are expected to publish a paper describing the study on Tuesday. The study has not yet been peer-reviewed.
We can confidently say that the P.1 variant changes the epidemiological characteristics of the virus in Manaus, but whether this is true in other cases is unknown,” said Dr. Nuno Faria, an associate professor at Oxford University and the study’s first author. “
He added: “There is no evidence yet that the P.1 variant does not respond to the vaccine – at least in terms of preventing severe disease.”
Which of the two variants (B.1.1.7 or P.1) is more infectious “is a very important question that needs to be addressed,” Farias said.
The researchers determined that the emergence of the P.1 variant dates back to Nov. 6, 2020, about a month before the second spike in cases in Manaus began. They found that the proportion of cases in Manaus infected with the P.1 variant increased from 0 to 87 percent in seven weeks.
The paper concludes, “Our findings further suggest that in the presence of evidence supporting the ability of the P.1 variant to alter epidemiological characteristics, it is unlikely that natural immunity weakening alone can explain the dynamic changes observed in Manaus.”
The paper continued, “Studies evaluating the effectiveness of real-world vaccines against the P.1 variant are urgently needed.”
The researchers also found that the emergence of the P.1 variant increased the likelihood of death due to new crown infections in Manaus by 10 to 80 percent. However, the authors caution that it is uncertain whether this means the variant is more lethal, or if it is the result of increased pressure on the city’s health care system, or both.
The P.1 variant has more than 17 mutations – which alter its genetic sequence and make it different from the virus originally found in Wuhan – including three key mutations in the stinger protein it uses to enter human cells.
Researchers in Brazil have been using gene sequencing technology developed by Oxford Nanopore (UK) to identify and track such variants. This technology was first used in Brazil during the Zika virus (Zika) outbreak in 2015.
Leila Luheshi, PhD, director of applied and clinical marketing at Oxford Nanopore, told the Financial Times that while the B.1.1.7 variant in the UK is similarly highly infectious to the P.1 variant – the B.1.1.7 variant’s infectiousness is thought to be about 1.5 times that of the previous variant – there is no evidence to date that the B.1.1.7 variant has evaded natural immunity in the same way. Studies to date also suggest that the current vaccine remains effective against the B.1.1.7 variant.
Luhaish said the concern about the P.1 variant is that “because of these mutations in the stinger protein …… we suspect that the vaccine will be less effective.” But she added that there is no clear evidence to support this theory.
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