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Global slowdown in virus spread – Mutations pose new challenges for vaccines

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Global slowdown in virus spread - Mutations pose new challenges for vaccines

A slowdown in the spread of SARS-CoV-2 is observed worldwide, but a new challenge is the spread of new strains, say the professors of the Therapeutic Clinic of the Medical School of the National and Kapodistrian University of Athens, Efstathios Kastlou and Thedos ΕΚΠΑ), which present the latest data.

For the sixth consecutive week, according to the World Health Organization, there is a decrease in new cases, with 2.4 million new cases last week (a decrease of about 11% compared to the previous week). The number of new deaths has also continued to decline over the past three weeks, with nearly 66,000 new deaths reported last week showing a 20% decrease compared to the previous week.

Only regions of Southeast Asia and the Eastern Mediterranean show a small increase of 2% and 7%, respectively. In America, the largest decrease in new cases in absolute numbers continues to be observed. Last week, the five countries with the highest number of new cases are still the US (480,467 new cases, down 29%), Brazil (316,221 new cases, down 1%), France (131,179 new cases, up 3%), Russia (92,843 new cases, decrease of 11%) and India (86,711 new cases, increase of 10%).

Mutations and vaccines

A new challenge is the proliferation of new SARS-CoV-2 strains involving three new strains (originally reported in the UK, South Africa and Brazil / Japan) while a new, fourth strain has recently been described in California, USA . For strain 20I / 501Y.V1 (from the United Kingdom) the WHO report reports increased transmissibility by (36% – 75%), a possible increase in the severity and mortality of the disease but does not appear to affect the efficacy of the three vaccines from Pfizer, Moderna and Astra-Zeneca / Oxford. For strain 20H / 501Y.V2 (South Africa) the WHO reports an increased transmissibility of approximately 50%, but probably no effect on the severity and mortality of the disease. As for the effectiveness of the vaccines, as far as the vaccines of Moderna and Pfizer-BioNTech are concerned, the possibility of neutralization seems to be affected, but it is unknown whether the protection against the development of the disease is affected. For the Novavax and Johnson & Johnson vaccines, they appear to provide reduced protection, while for the AstraZeneca / Oxford vaccine, its efficacy appears to be significantly affected. Finally, the third strain (20J / 501Y.V3- Brazil / Japan) appears to be associated with increased transmissibility but there is still no evidence of efficacy in the protection provided by the various vaccines against it.

Moderna says a new version of the vaccine is tailored to kill the strain infection from South Africa. A quantity of the vaccine has already been sent to the US Institutes of Health to test whether the modified vaccine will stimulate a strong immune response. Moderna is also testing the existing two-dose vaccine to determine if a third dose will provide a strong boost to immunity to the South African mutation. Pfizer, with an approved mRNA vaccine, said it was taking similar precautions to determine if vaccines targeting the variant should be produced or if the initial vaccination would be sufficient. The original Pfizer and Moderna vaccines have been shown to kill the South African mutation in the laboratory but with reduced response rates.

On February 27, 2021, the FDA approved the Johnson & Johnson vaccine, which is the third vaccine to be available in the United States. During the long debate, Johnson & Johnson researchers argued that the single-dose vaccine was 66% effective in protecting against moderate to severe disease in a large, global clinical trial and 85% effective against severe cases. .

A fourth new strain of SARS-CoV-2 virus, first identified and now spreading to California, appears to be somewhat more contagious and increases the risk of serious illness and the need for ICU and death, according to the first epidemiological data. In addition, it may show some resistance to neutralizing antibodies, but the data are very early, and in a small number of cases.


Source: politis.com.cy

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