Omicron Variant Symptoms, Vaccine, Danger | How effective are vaccines Covid 19?

Omicron Variant Symptoms

Omicron is spreading at a rate that we have not seen with any previous variant, warned Tedros Adhanom Ghebreyesus, Director of WHO on December 15, 2021. What are the Omicron variant symptoms?

According to data from South Africa regarding the Omicron variant symptoms: most infections are described as mild, “with healings typically within three days,” said Ryan Noach, managing director of Discovery Health, the south’s leading private African health insurance organization.

The most frequently reported early symptom is a sore throat, followed by nasal congestion (stuffy nose), dry cough and myalgia (stiffness), more specifically manifested by lower back pain.

Data from Discovery Health further indicated that children under the age of 18 had a 20% higher risk of admissions for complications when infected with Omicron compared to other variants. “Most children infected with Omicron complained of headaches, sore throats, nasal congestion and fever, which usually went away within three days,” said Shirley Collie (Discovery Health), reports the Washington Post.

What is Omicron’s contagion (spread)?

“The impact of the mutations observed for the Omicron viruses on contagiousness is confirmed, both due to an immune escape linked to mutations localized on the spike protein, and to its increased replicative capacity. Transmission is markedly increased compared to the variant Delta “confirms the Scientific Council in an Opinion of December 17.

According to preliminary studies reported by Public Health France, “Omicron is approximately 3 times more transmissible than Delta” which itself was 60% more transmissible than the 2020 Alpha variant.

Dangerousity

More or less dangerous? The South African scientists behind the identification of the Omicron variant immediately declared that “this line has a high number of mutations previously seen in other variants of SARS-CoV-2, variants of interest ( VOI) or variants of concern (VOC) but also other mutations which are new “.

The WHO has rated the risk of Omicron spreading globally as “high”. “It is not yet clear whether infection with Omicron causes more severe disease compared to infections with other variants, including Delta. Preliminary data suggests that there is an increase in hospitalization rates in South Africa, but this may be due to the increase in the overall number of people infected, rather than a specific infection with Omicron, “said the WHO.

While preliminary data tended to show a lower virulence of Omicron, the French Scientific Council believes to date that “there is no objective evidence to say that the Omicron variant would lead to clinical forms less severe than those observed; with its predecessors”.

According to results published by Imperial College London on December 16 based on people who tested positive for Covid-19 during a PCR test in England between November 29 and December 11, 2021 (333,000 cases including 122,000 from Delta and 1846 of Omicron), there is no evidence to show that Omicron has a different gravity than Delta.

On the other hand, scientists indicate that “Omicron was associated with a risk of reinfection 5.4 times higher than Delta”. A past infection with Covid would only protect up to 19% against reinfection by this new variant. Same figure for people vaccinated with two doses.

How effective are vaccines?

Work is underway to study the potential for immune escape of the Omicron variant in the face of the vaccine. “Based on our understanding of the mutations in this lineage, partial immune evasion is likely,” the South African researchers immediately indicated.

The Omicron variant is the most divergent variant in terms of mutations since the start of the pandemic. According to the results of the first studies, the members of the French Scientific Council indicated on December 17, 2021 that “the protection 6 months after two doses of messenger RNA vaccine was estimated by modeling at 40% against symptomatic infection, and 80% against severe disease. A booster dose with a messenger RNA would increase this protection to 86% against symptomatic infection, and 98% against severe forms”.

According to a study pre-published on December 16, 2021 in Biorxiv by researchers from the Institut Pasteur and the Vaccine Research Institute, in collaboration with the KU Leuven (Leuven, Belgium), the CHR of Orléans, the European Hospital Georges Pompidou (AP -HP), Inserm and CNRS, the antibodies present in the blood of people who have received two doses of the Pfizer vaccine or the AstraZeneca vaccine are no longer able to neutralize Omicron 5 months after vaccination.

This loss of efficacy is also observed in people infected with SARS-CoV-2 in the previous 12 months. “A third booster dose with the Pfizer vaccine, or the injection of one dose of vaccine in people with a previous infection, greatly increases antibody levels, to a level sufficient to neutralize Omicron,” scientists show. Similar conclusions were made by English researchers at Imperial College London on December 17, 2021.

According to their observations, the efficacy of the vaccine (Pfizer or AstraZeneca) against symptomatic infection with Omicron is between 0 and 20% after two doses and between 55% and 80% after a booster dose. “There is a huge amount of uncertainty in these modeled estimates,” however stressed Dr Clive Dix, former Chairman of the UK Vaccine Task Force, calling for not “to overinterpret the data”.

“We can only be confident about the impact of the boosters against Omicron when we have another month of real data on the number of intensive care hospitalizations and deaths,” he said. According to a South African study published on December 14, 2021 by Private Health Insurance Discovery and on the results of 78,000 PCR tests carried out between November 15 and December 7, 2021, “the double dose of the Pfizer vaccine shows an efficacy of 70% in the reduction of hospitalizations “and an efficiency of 33% against the risk of contamination.

Pfizer-BioNTech continue to advance the development of a vaccine specific to the Omicron variant and expects it to be available by March 2022. Johnson & Johnson and Moderna Laboratories have also started work on a new version. of their vaccine. Tuesday, November 30, 2021, the CEO of the Moderna laboratory, Stéphane Bancel, interviewed in the Financial Times, confirmed a “significant drop” in vaccine efficacy and stressed that “most experts believed that such a highly mutated variant would not emerge; before a year or two”.