symptoms, vaccine resistance, contagiousness, what do we know? –

by time news

The answers to the most frequently asked questions about the new Omicron variant, which is growing especially in South Africa. Where was born? Like? Could it undermine the effectiveness of vaccines? What characteristics does it have? Are the symptoms of Covid changing?

What are the characteristics of variant B.1.1.529?

The variant identified at the genetic sequence level with the initials B.1.1.529, which took the Greek name Omicron, simultaneously presents almost all the mutations we know of from the variants of concern (VOC) Alpha, Beta, Gamma and Delta and more. Specifically, it has 32 mutations in the spike protein (the part of the virus that most vaccines use to trigger the immune system against Covid). Some mutations have never been seen, others have been linked to the ability of a variant to be more transmissible, escape the immunity given by vaccines and certain drug treatments.
Line B.1.1.529 already indicated by WHO as the variant under monitoring. However, it is expected to be classified as a variant of interest (VOI) or variant of concern (VOC) shortly.

Where was born?

The first sequenced cases were uploaded separately (and almost simultaneously) from laboratories in Botswana and from Hong Kong (where the variant arrived carried by a traveler from South Africa). South Africa followed closely on November 22 after analysis of samples collected between November 14 and 23. It is not known which is the country of origin of the variant, since the identification depends on the tracking capacity of the laboratories: it is South Africa, Botswana and Kenya that have a higher sequencing capacity than other African countries. More than 80% of the 5.4 million SARS-CoV-2 genomes uploaded to Gisaid’s international database come from North America and Europe.

How widespread?

We still don’t know. In many areas of the world, borders are open and travel has resumed: identifying cases could only be a matter of time. For now, we know that the positives are increasing rapidly in South Africa, particularly in Gauteng (an urban area that includes Pretoria and Johannesburg), but also in the north-west of the country and in Limpopo. Positive rates in Tshwane (part of Guateng) have increased in the past 3 weeks from less than 1% to over 30%. South Africa reported 2,465 new cases on Thursday, a 321% increase from the previous week. It is estimated that about 90% are due to the new variant, which in the country has supplanted the Delta. Officially, there are 85 confirmed cases (from genetic testing) in the world (77 in South Africa, 4 in Botswana, 2 in Hong Kong, 1 in Belgium and 1 in Israel), but there are investigations on other possible introductions (including others 2 in Israel, plus 990 cases to be analyzed in South Africa).

Do the symptoms change?

The cases are still few and the surveillance started a few days ago. The National Institute for Communicable Diseases South African (NICD), the public institute of reference on infectious diseases, writes: There are currently no unusual symptoms reported following infection with variant B.1.1.529 and, as with other variants, some individuals are asymptomatic.

Does variant B.1.1.529 puncture vaccines?

Since the start of the pandemic, over 1,500 different strains of the SARS-CoV-2 virus have been recognized and for now there are four variants defined as worrying by the World Health Organization (WHO). South African NICD experts state: Based on our understanding of mutations in this lineage, partial immune escape is likely, but vaccines are likely to still offer high levels of protection against hospitalization and death. Other scientists said they were more alarmed, because the genetic profile of the variant has several traits judged unfavorable. However, they claim, mutations often work together, so it’s impossible to predict what this particular combination might mean. There have been reports of vaccinated reinfections (even with the third dose). From the genome of the new variant other not very reassuring details can be deduced: we know exactly which parts of the virus recognize the therapies based on monoclonal antibodies and some of these have changed in the lineage B.1.1.529. Obviously soon for the conclusions, but there are reasons for alarm.

How will the new variant affect the spread of the pandemic?

It is not known whether and how much the new variant will be more transmissible or more lethal, although the WHO has said that the first signals would demonstrate a greater transmission capacity and a greater capacity for reinfection. All the other major variants were recognized by vaccines, which remained valid and protective with respect to the possibility of being hospitalized or dying, but lost effectiveness (after about six months, however) with respect to the possibility of being infected. There is no reason to think it will be different. It still takes at least two to three weeks of monitoring and laboratory testing to glimpse any response. The Delta variant – it must be remembered – has supplanted all the others thanks to its transmission capacity.

Will mutations in the variant affect the sensitivity of the tests currently in use?

Lineage B.1.1.529 has at least one advantage for diagnostic systems: it has a deletion (at position 69-70) within the S gene which has enabled rapid identification of this variant in South Africa and will allow continuous monitoring regardless of available sequence data (which are used for confirmations). The overall sensitivity of the PCR test (the molecular swab) is unlikely to be affected, as is that of the rapid antigen tests.

So can one understand from the buffer alone whether it is variant B.1.1.529?

The swab analysis looks for three different target genes in the RNA of the virus, named S, N and Orf. When all three are present, we are faced with a variant fully recognized by diagnostic systems – explains al Courier service Nicola D’Alterio, general director of the Experimental Zooprophylactic Institute of Abruzzo and Molise (IZSAM) -. In the new variant the S gene does not exist, that is “negative S”. Therefore, there is a high probability that at this time in South Africa a “negative S” swab is actually associated with the new variant, but to be sure it is necessary to sequence the genome because other variants may have the same characteristic. Even Alpha, for example, “S negative”, but the strain never spread much in Africa and almost extinct in the world, supplanted by the Delta.

Do you know how the new variant was born? What if a zero patient was identified?

Scientists have argued for the evolution of variant B.1.1.529 during a chronic infection of an immunocompromised person, possibly an untreated HIV or AIDS patient. Immunocompromised people could act as a reservoir for variants, as they can harbor the virus for several weeks, during which time SARS-CoV-2 continues to replicate. However, the virus also mutates in unvaccinated and vaccinated people. The variant could have sprung up anywhere. The rule that the more the virus is free to circulate (in poorly vaccinated and therefore still susceptible populations), the more it has the possibility of mutating, for no epidemic in any country has ever been able to trace back to patient zero, but only to index cases (such as that of Hong Kong, which identified the first case of a variant in the country starting from a return traveler).

What can we do?

Variants arise when and where the virus is left free to circulate. This implies that vaccinations (and second-rate restrictions) have the power to hold him back. The global coverage of the first dose in the world of 53%, but concentrated in very few countries. No one is safe until everyone is safe, as the WHO reiterates. The goal is to vaccinate as many people as possible and in as many states as possible: coverage of the first dose is 62% in Europe, 69% in the US and only 11% in Africa. With regard to the immediate measures to curb the circulation of the new variant, the countries are equipping themselves with some restrictions which, for now, mainly concern flights.

November 26, 2021 (change November 26, 2021 | 19:13)

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