The largest Covid-19 genomic surveillance study in Latin America was published this Thursday (23) in Science, one of the most prestigious academic journals in the world. The research, focused on the spread of the virus in Brazil, sequenced 427 genomes of the new coronavirus (SARS-CoV-2) from 21 Brazilian states and was carried out jointly by 15 Brazilian institutions, including Unicamp, as well as British institutions. Among the results, the researchers detected more than 100 distinct introductions of the virus in Brazil.
"The data shows that there were several events of introduction of the virus in Brazil, more than 100, mainly from people who were returning from Europe and the United States. From this massive introduction, before the containment and social isolation events, the virus it spread mainly in three large groups, which were more successful and spread throughout Brazil", explains professor at the Institute of Biology (IB) at Unicamp José Luiz Proença Módena, who was involved in the study. The researcher coordinates the IB's Emerging Virus Studies Laboratory (LEVE), whose team also participated in the research.
In the three large groups of preponderant viruses, which comprised 76% of the viruses detected until April, José Luiz notes that mutations associated with severe forms of Covid-19 were identified. “They all have a point mutation in the spike protein, which is a virus protein associated with pathogenicity, with more severe disease and increased viral load,” he says.
Most virus introductions in Brazil were identified in capitals with the highest incidence of international flights, such as São Paulo, Minas Gerais, Ceará and Rio de Janeiro. Only a small portion of these introductions resulted in lineages that spread throughout the country through community transmission, that is, through transmissions whose origin of infection is not possible to trace and which circulate among people who have not traveled.
Insufficient isolation measures
The results demonstrate that interventions such as the closure of schools and businesses at the end of March, although insufficient, helped to reduce the virus transmission rate. Initially, this rate was above 3, which means that one person transmitted the virus to three people. After the measures, the values dropped to between 1 and 1,6, both in São Paulo and Rio de Janeiro.
“As a result of social isolation measures, the rate of spread of the virus drops, but it is not enough to stop the transmission of the virus, which continues to spread interestingly now from long distances through the traffic of people, including the area network within Brazil, arriving to all ends of the country”, says José Luiz.
Cooperation between institutions
The work began with an activity by the Joint Brazil-United Kingdom Center for Arbovirus Discovery, Diagnosis, Genomics and Epidemiology (CADDE), funded by Fapesp. The institutions involved in the research are: State University of Campinas (Unicamp); University of São Paulo (USP); Federal University of Minas Gerais (UFMG); Federal University of Rio de Janeiro (UFRJ); Fundação Getúlio Vargas (FGV); Federal University of Uberlândia (UFU); Federal University of Roraima (UFRR); Faculty of Medicine of São José do Rio Preto; Institute of Applied Economic Research (Ipea) and National Scientific Computing Laboratory (LNCC). Among the British institutions involved is the University of Oxford.
In Campinas and the region, professor José Luiz Módena highlights that there was a great effort from LEVE and health professionals from Unicamp: team from the Clinical Pathology Laboratory and Epidemiological Surveillance Center at Hospital de Clínicas, professionals from the Health Center of Community (Cecom) and professionals from Sumaré Hospital.
From Unicamp, in addition to José Luiz Módena, the authors of the study are: Mariene Amorim; Fabiana Granja; Marcia T. Garcia; Maria Luiza Moretti; Maurício Perroud Jr.; Terezinha Castiñeiras; Camila Simeoni; Julia Forato; Andrei Sposito; Angelica Schreiber; Magnum Santos and Patricia AF Leme.
"The effort made it possible for us to sequence, in Campinas, 66 complete genomes of this virus, which helped in the construction of data that is now little published", he assesses. He also states that the research is an “example of how the transnational, multicentric approach can quickly contribute to knowledge and the construction of quality science that can help solve society’s problems”.
Check out the article published in Science.
See also the interview with professor José Luiz Proença Módena for the series Em que pé está:
