Omicron is a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant. In fact, it was classified by the WHO on November 26, 2021 as the fifth variant of concern "B.1.529" originating from south Africa. Therefore, Due to its fast spreading (2 days average doubling time), only until January 8, 2022, the virus entered 115 countries with 552,191 cases reported and 115 deaths.
Antibodies efficacy:
Omicron has spike proteins; in other words, its key epitope of neutralizing antibodies are mutated more than 50 times. Hence, it's about 11 times the other variants mutation. Therefore, testing several antibodies showed that some may lose their neutralizing activity against the virus.
Does the booster work against omicron?
As a matter of fact, the symptoms are milder than delta variant. However, whether you acquired covid-19 or been vaccinated, it only offers little help or non at all. A study showed that the sera neutralizing effect of people with 2 doses was null, but the sera neutralizing activity of people with booster immunization was effective against omicron variant infection.
Can I get omicron if I had Covid-19 before?
Yes. Certainly, the variant is highly mutated; thus, it evades the immunity provided by a previous infection or the vaccine.
References:
-Desingu PA, Nagarajan K, Dhama K. Emergence of Omicron third lineage BA.3 and its importance. J Med Virol. 2022 Jan 18. doi: 10.1002/jmv.27601. Epub ahead of print. PMID: 35043399.
-Singhal T. The Emergence of Omicron: Challenging Times Are Here Again! Indian J Pediatr. 2022 Jan 13:1–7. doi: 10.1007/s12098-022-04077-4. Epub ahead of print. PMID: 35025038; PMCID: PMC8756165.
-Gruell H, Vanshylla K, Tober-Lau P, Hillus D, Schommers P, Lehmann C, Kurth F, Sander LE, Klein F. mRNA booster immunization elicits potent neutralizing serum activity against the SARS-CoV-2 Omicron variant. Nat Med. 2022 Jan 19. doi: 10.1038/s41591-021-01676-0. Epub ahead of print. PMID: 35046572.
