Via Fiocruz: COVID-19: more intense virus circulation has driven peaks of cases and P.1 in Amazonas. Excerpt:
In a paper published (5/25) in Nature Medicine, researchers of the Fiocruz Genomic Network and of partner institutions point to the cause of the increase in the number of COVID-19 cases in the state of Amazonas and of the successive replacements of lineages of Sars-CoV-2. The study shows that these factors have been boosted by a combination of reduced social distancing measures and the appearance of a new, more transmissible form of the virus, the P.1 variation, identified in mid-November 2020. This variant has caused an exponential increase in case numbers, thus establishing a second wave of the epidemic in the state.
“We have a history of respiratory viral diseases following a different calendar here in Amazonas: our peaks normally take place before other states. The new, more infectious variant appeared in a period of less social distancing. P.1 was the consequence of virus circulation and it later caused the collapse of the public health system in Amazonas”, explains Felipe Naveca, researcher and vice-director of Research and Innovation of the Leônidas & Maria Deane Institute (ILMD/Fiocruz Amazônia).
The state of Amazonas has been through two waves of disease increase, the first at the beginning and the second at the end of 2020. For the genomic epidemiology study published on Nature, 250 sequences of the complete genome of Sars-CoV-2 were generated, all of high quality, from individuals of 25 municipalities, between 16 March 2020 and 13 January 2021.
The result reveals that the first increase in COVID-19 cases between March and May) was boosted mainly by the dissemination of the B.1.195 lineage, then replaced by B.1.1.28 between May and June 2020. The situation remained stable between June and November, with small variations. The second phase took place in mid-December 2020 with the emergence of the P.1 variant and the consequent explosion in the number of cases.
For Felipe Naveca, the fact that P.1 hit young people as often as it affected older people may be related to more exposure by the first, be it for work-related issues or due to less social distancing by choice. “They got exposed when they went back to work as much as they did for social reasons. It appears that this was terrible in a context of circulation of an even more infectious variant”, he comments.
According to the researchers, the variant of concern, P.1, contains 21 lineage-defining mutations, including ten in the spike protein (L18F, T20N, P26S, D138Y, R190S, K417T, E484K, N501Y, H655Y, and T1027I). It was first announced on January 10 this year, after a study on four people who had returned to Japan after going through the state of Amazonas. The variant was therefore acknowledged as a lineage that emerged in the state capital, Manaus.
