Omicron subspecies BA.4 and BA.5 are rapidly sweeping the world and becoming new popular subspecies. So, how strong are the immune evasion effects of BA.4 and BA.5 subspecies? Recently, a study published in the journal Lancet ID showed that the neutralizing activity of the current multiple monoclonal antibodies against BA.4 and BA.5 subspecies was significantly reduced, while vaccine-induced antibodies and convalescent plasma were more effective against BA. The neutralizing activity of subspecies .4 and BA.5 is also lower than that of previous subspecies.
Omicron subspecies BA.4 and BA.5 (first detected in South Africa) are spreading rapidly, and have surpassed BA.2 in European and American countries, becoming second only to BA.2.12.1 (first detected in the United States) popular subspecies. The S protein of BA.4 and BA.5 is the same at the protein level, but is different from the S protein gene mutation of BA.2.12.1, but are they different from BA.1 and BA.1 in terms of neutralization sensitivity? BA.2, which remains largely unknown.
researchers analyzed the neutralizing activity of several common monoclonal antibodies against BA.2.12.1 and BA.4/BA.5 (EC50, half maximum effect concentration, the lower the better the neutralizing activity), as follows As shown in the figure, only bebtolovimab still shows significant neutralizing activity; cilgavimab, cilgavimab/Tixagevimab still have a certain neutralizing activity against BA.4/BA.5, but less than BA.1, BA.2, and BA.2.12. The neutralizing activity of 1 was reduced.
Next, the researchers analyzed the effects of BA.2.12.1 and BA.4/BA on the plasma of 10 unvaccinated convalescent patients (5 men and women aged 20-71 years) who had previously been infected with BA.2. .5, the results show that the neutralizing effect on BA.2.12.1 is similar to that of BA.2, but the neutralizing effect on BA.4/BA.5 is significantly reduced.
The researchers further analyzed the neutralizing effect of antibodies induced by vaccine vaccination. The results showed that after three injections of BNT162b2 vaccine, compared with B.1, the neutralizing effect on BA.2.12.1 was reduced by 6.1 times, and the neutralizing effect on BA.4/BA.5 was reduced by 8.1 times.
The results of this study show that the neutralizing effect of most monoclonal antibodies on BA.4/BA.5 and BA.2.12.1 is significantly reduced, but bebtolovimab is still effective against any current Omicron subspecies. In addition, the immune evasion of BA.2.12.1 is only moderately increased compared to BA.2, while the immune evasion of BA.4 and BA.5 is more obvious and is more likely to occur in vaccinated people and those infected with BA.1 and BA. .2 spread among recovered patients.
▌Original link:
https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(22)00422-4/fulltext
BA.4/BA.5 subspecies is "more cunning", most monoclonal antibodies invalid
