Vaccines act against severe covid, even with a new variant

Study on Ômicron is by South African scientists

Published in 03/12/2021 - 11:30 By RTP - Cidade do Cabo

South African scientists have concluded that existing covid-19 vaccines prevent severe disease with the Ômicron variant of SARS-CoV-2. Preliminary advances in a study indicate that the PCR test allows us to see if the contagion is with the new mutation, without having to segment the genome.

The South African Genome Surveillance Network (NGS-SA) presented the studies on Ômicron to Parliament's Health Committee.

Although they still need time to adjust the data, on what they consider the beginning of the fourth wave of the pandemic, they guarantee that they are focused on transmissibility and the effect of the immunity that vaccines provide.

"The genetics of Ômicron is completely different from the Delta variant or from previous variants," said Richard Lessels, an expert in infectious diseases.

Scientists still don't know if the incubation period remains at an average of five days. However, Lessels guarantees that "vaccines are the tool that can prevent serious illness and hospitalization".

“We are concerned not so much with the number of mutations as where they are concentrated, because many of them do so at the peak of the protein and specifically in key parts that are important to access our cells. We don't know if the antibodies are capable of dealing with them”, he added.

The expert highlighted that, “although most positive cases with the new variant have mild symptoms, it is too early to tell the level of danger of Ômicron, because it was detected very recently. We don't know if we're going to see more serious cases.”

The variant is already present in all the provinces of South Africa. The question of experts is whether it will replace the Delta “which was spreading at very low levels”. Lessels claims that the PCR test is capable of detecting the new variant without the need to sequence the genome.

“If one of the three PCR signals or targets is negative and the other two are positive, then the test is still positive, but something different is observed. It is not possible to detect the Skipe gene. And that's what happened in the Lancet laboratory, in Gauteng [province in the north of South Africa], where they found that some positive cases had this mark: the knockout of the gene, which does not happen with the Delta variant. Therefore, with PCR we can monitor the tracking of Ômicron in real time, it is not necessary to have the complete genetic sequence, which usually takes two weeks in the laboratory”, he explained.

South Africa's National Institute of Infectious Diseases confirmed in November that of 249 localized sequences, 183 were from Ômicron. Post-covid-19 immunity, whose duration is unknown, does not offer protection against the new variant.

Gauteng province (the most populous in the country and which includes the cities of Pretoria and Johannesburg) continues to have the most daily positive cases, followed by KuaZulu-Natal and the Western Cape.

Eight of Gauteng's 15 million inhabitants have not been vaccinated, and the transmission rate has gone from one to 2.3.

“Of course unvaccinated young people are a big concern. We continue to send the message that being vaccinated is important because people who are immunized are showing milder symptoms,” said David Makhura, Prime Minister of Gauteng.

Ômicron has been detected in more than 20 countries, but South Africa and Botswana continue to account for 62% of newly identified cases worldwide.

Text translated using artificial intelligence.

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