In early January this year, Omicron was discovered in Tianjin, officially invading the mainland region of China and subsequently causing a localized epidemic in many places.
The World Health Organization first confirmed the new coronavirus B.1.1.529 mutant strain-Omicron on November 24, 2021.Compared with the original strain at the beginning of the outbreak, the Omicron variant genome has 59 mutations causing significant amino acid changes, including 37 nonsynonymous mutations located in the stinging protein of the neutralizing antibody target, which This series of mutations also led to a higher infectivity and breakthrough infection of the Omicron strain.
Can breakthrough infections occur even after vaccination?
Yes, as the level of antibodies in the body changes over time after vaccination, there are corresponding changes. Cases of vaccinated infections have shown that the vaccine is effective in preventing serious illness and death in Omicron, but not in preventing "breakthrough" infections. In general, Omicron has increased immune escape and infectivity, reduced pathogenicity and is predominantly asymptomatic, and its breakthrough infection and symptoms are related to multiple factors.
Compared to beta and delta strains, a higher rate of asymptomatic Omicron infections has been shown through multiple studies. The rate of asymptomatic Omicron carriers was 27%, much higher than the beta, delta strain at 2.6%, and their rapid new crown nucleic acid test showed that 48% of tested samples had CT values <25 and 18% below 20, indicating that the viral titers of asymptomatic individuals with Omicron rapid new crown nucleic acid test were high and also transmissible.
And studies have shown that Omicron has a long viral shedding time: a study of RNA levels and shedding time of upper respiratory viruses in asymptomatic/mildly ill patients with Omicron in Japan showed that mild or symptomatic infections transmit infectious viruses 6-9 days after onset or diagnosis, even after symptoms have disappeared; and some asymptomatic infections were still detected as weakly positive by the New Crown Nucleic Acid Rapid Test 14 days after diagnosis .
Can't vaccination deal with Omicron breakthrough infections?
The large number of breakthrough Omicron vaccine infections suggests that existing vaccines are less effective in preventing Omicron infection. Studies have shown a 30-fold reduction in serum-neutralizing antibody activity against Omicron 2-4 weeks after 2 doses of mRNA vaccine; six months later, subjects had no serum-neutralizing activity against Omicron. Over 90% of sera from subjects who received the booster (third dose) for 1-4 weeks showed neutralizing activity, but there was a 14-fold reduction in neutralizing activity to Omicron compared to other strains.
How do we cope with such a cunning Omicron strain?
First of all: intensify vaccination, which is always the most efficient and least expensive form of protection, no matter how the virus changes.
The second is to perform the New Coronavirus Rapid Test (NCRT). No matter how the virus changes, the NCRT is still valid for the specific fragments of the virus. The NSCR is the "gold standard" for diagnosing patients with NSCN, as it has multiple gene fragments as targets and can accurately identify the virus. In addition, the Nucleic Acid Rapid Test System has been developed for a variety of emergency applications, such as airports, customs, fever clinics, etc., which is very important to prevent the entry of mutated strains of NCC virus into China.
