The point in collaboration with Carlo Federico Perno, director of the Microbiology Unit, Bambino Ges pediatric hospital in Rome
Is the rise in positives worrying?
More time is needed to get a precise picture of the trend, but there are undoubtedly signs of a resumption of infections. Omicron and its sub-variants are highly transmissible and have reached 100% diffusion in Italy.
Do vaccines protect us?
Those who have completed the vaccination course with three doses have good protection against severe disease. We know that Omicron infects at the level of the nose, which is not defended by antibodies. In fact, vaccination forms a second trench that shields the lower respiratory tract (bronchi and lungs). In most vaccinees, the infection caused by Omicron presents with mild symptoms, such as a runny nose, sore throat, or headache. A study by the UK Health Safety Agency, published in the New England Journal of Medicine
, shows that the third dose protection against Omicron begins to decline after two months, while continuing to protect against severe disease. The researchers looked at data from more than one million people infected between November and January. Compared to infection with mild symptoms, the third dose with Pfizer increased protection to 67%, but the value dropped to 46% after 10 or more weeks. The booster with Moderna was 74% effective against mild disease after 2-4 weeks and the value dropped to 64% after 5-9 weeks.
Can the virus mutate again?
Yes, we will likely see the emergence of new Omicron sub-variants. The risk of generating an even more transmissible version of those in circulation and able to escape vaccines. From this point of view, BA.2 itself could become worrying if it significantly increased its diffusion, because it presents some mutations in the Spike protein which, in studies in vitro, have overcome the monoclonal antibody barrier. It comforts the precedent of Beta and Gamma, variants with a high degree of immune escape but which have not been able to become dominant. Furthermore, we currently have no evidence of BA.2’s ability to circumvent vaccine protection.
(Carlo Federico Perno, director of the Microbiology Unit, Bambino Ges pediatric hospital in Rome, collaborated)
March 9, 2022 (change March 9, 2022 | 10:43)
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