Source: [Health Times]
On July 6, the New England Journal of Medicine published online the article "The neutralization effect of inactivated vaccine and ZF2001 vaccine on the Omickron mutation strain", and systematically evaluated the immune effect of inactivated vaccine and recombinant protein vaccine (ZF2001 vaccine) on the Omickron mutation strain of the new coronavirus. Studies have shown that the immune effect of several commonly used vaccines in China on BA.4 and BA.5 variants has been greatly reduced.
article stated that in order to better prevent the immune escape of current mutant strains, especially BA.4 and BA.5 strains and possible future exponential mutant strains, newer enhanced vaccines are needed.
According to the latest global COVID-19 weekly report released by the World Health Organization on July 6, the number of new COVID-19 cases in the world has risen for the fourth consecutive week, reaching the highest level since March this year. The main reason for the increase in the number of cases is that the Omickron BA.4 and BA.5 variants with stronger infectiousness and immune escape ability have triggered a new wave of infections around the world.
Academician Gao Fu's team evaluated the neutralizing antibody titers in the serum samples of vaccinated patients against the original strain of the new coronavirus and multiple Omickron variant strains, including BA.4, BA.5, etc. These vaccinators have adopted different vaccination methods: receive 3 doses of inactivated vaccine (Scientific and Sinopharm vaccine); receive 3 doses of recombinant protein vaccine (Zhifei ZF2001); or sequential vaccination, that is, receive 2 doses of inactivated vaccine + 1 dose of recombinant protein vaccine.
study found that the Omickron mutant strain has strong immune escape ability. The neutralizing antibody titers against the variant strain in the serum of all vaccinators were significantly lower than the corresponding titers against the original strain , with the lowest neutralizing antibody titers against the BA.4 and BA.5 variants.
ZF2001 and the neutralizing antibody against the Omickron variant of
Specifically, the neutralization effects of BA.1.1 and BA.2 are similar to BA.1 (within the range of 1.5 factors). Compared with BA.2.12.1, there is an additional L452Q mutation in the receptor binding domain (RBD) on its spike protein, and therefore has a lower neutralization rate of 1.4-1.7-fold. In each inoculation group, the neutralizing antibody titers were 2.1-2.6 times lower than those for the BA.2 variant. This finding suggests that the two mutations of L452R and F486V of RBD result in low antibody neutralization efficiency triggered by vaccines based on the original strain sequence design.
sequentially strengthened the neutralizing antibody titer in the inoculation group is higher than that in the three-acupuncture inactivation group
study found that the neutralizing antibody titer increases with the increase in the interval between the second dose and the third dose. For vaccinators with a interval of 4-6 months between the second and third doses, the neutralizing antibody titers for the original strain isolates were nearly 10 times higher, and for all Omickron variants, compared with those with a interval of 1 month between the two inoculations. The vaccine in the
long-spaced group was 100% seropositive for all Omickron variants. Among the serum samples obtained 6 months after the last dose of the vaccine in the long-spaced group, the neutralizing antibody titers and serum positive rates for all Omickron variants were higher than those obtained 1 month after the last dose of the short-spaced subgroup.
In addition, the vaccination group that received sequential enhancement (i.e., 2 inactivated vaccine + 1 recombinant protein vaccine) had higher neutralizing antibody titers against the original strain and all variant strains than the vaccination group that received the three inactivated vaccine. (Wang Yuan)
This article comes from [Health Times] and only represents the author's views. National Party Media Information Public Platform provides information release and dissemination services.
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