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Heterologous SARS-CoV-2 vaccine has a strong immune force
Heterologous SARS-CoV-2 vaccine has a strong immune forces immunityAccording to recent immunogenicity studies, compared with adenovirus-based ChAdOx1 (AstraZeneca) vaccines and mRNA vaccines, heterologous doses induced a stronger immune response than the homologous ChAdOx1 vaccine series
.
.
Despite the successful development of multiple vaccines against the coronavirus SARS COV-2, the continued emergence of variants of concern and the limited distribution of vaccines worldwide continue to limit the effectiveness of vaccines
.
A new problem facing global vaccines is the occurrence of rare events such as thrombosis and thrombocytopenia syndrome related to adenovirus vaccines
Despite the successful development of multiple vaccines against the coronavirus SARS COV-2, the continued emergence of variants of concern and the limited distribution of vaccines worldwide continue to limit the effectiveness of vaccines
In the recent Nature magazine, Barros Martins et al.
Barros Martins et al.
reported that, compared with the results obtained by homologous ChAd-ChAd vaccination, the ChAd-BNT vaccination strategy resulted in a significantly enhanced immune response to immunoglobulin G (IgG) and IgA against the SARS-CoV-2 spike protein, and Robust, anti-SARS-CoV-2α (B.
1.
1.
7), β (B.
1.
351) and γ (P.
1) variants of neutralizing antibody titers increased by 20 times to more than 60 times
.
These neutralizing titers were approximately three times higher than the titers in the serum of the BNT-BNT dose group (although the interval between dose 1 and dose 2 was different), and the titers of IgG and IgA subclasses were higher
Barros Martins et al.
Compared with the homologous ChAd/ChAd vaccine, the heterologous ChAd/BNT vaccine induces a stronger anti-SARS-COV-2 spinous T cell response
.
.
After ChAd- mRNA (BNT162b2 or mRNA-1273) or mRNA-mRNA vaccination,
Schmidt et al .
showed that IgG antibody titers against SARS-CoV-2 spike protein and receptor binding domain were significantly higher than homologous ChAd-ChAd After vaccination .
After ChAd- mRNA (BNT162b2 or mRNA-1273) or mRNA-mRNA vaccination,
Schmidt et al.
further proved that in the ChAd-mRNA group, there is a comparable multifunctional, spike protein-specific CD4+ T cell response, but the CD8+ T cell response is stronger
.
further proved that in the ChAd-mRNA group, there is a comparable multifunctional, spike protein-specific CD4+ T cell response, but the CD8+ T cell response is stronger
.
Ratio compared ChAdOx1 nCoV-19 inoculated homology vector / vector vaccine (n = 55), between dissimilar individuals ChAdOx1 nCoV-19 vector / the mRNA vaccine (n = 96) and the homologous mRNA / mRNA vaccines (n = 62) of Immune response
.
.
Immunity between individuals vaccinated with homologous ChAdOx1 nCoV-19 vector/vector vaccine (n = 55), heterologous ChAdOx1 nCoV-19 vector/mRNA vaccine (n = 96), and homologous mRNA/mRNA vaccine (n = 62) Answer
The third study recently published in The Lancet provides additional evidence that the Lancet heterologous ChAd-mRNA vaccine method is well tolerated and can stimulate a strong IgG and neutralizing antibody response
Taken together, these studies show that the immunogenicity results of mixed vaccination are improved, and that this strategy may be superior to the homologous prime-boost regimen in terms of cell response and neutralization of variants
.
.
The immunogenicity results of the mixed vaccination were improved and indicated that this strategy may be superior to the homologous prime-boost regimen in terms of cellular response and neutralization of variants
.
As these new studies show, verifying the immunogenicity and reactogenicity of "mixed and matched" doses of different approved vaccines may provide a solution that can help alleviate supply shortages and disruptions
.
The improved immunogenicity results also indicate that the heterologous vaccine approach can overcome the limitations of a single vaccine platform
.
The immunogenicity of adenovirus vector vaccines is limited by pre-existing neutralizing antibodies against common adenovirus serotypes in human contact, and may impair the immune response to SARS-CoV-2 spike protein
.
Extensive preclinical and early clinical studies, especially the development of human immunodeficiency virus vaccines, have long demonstrated the potential immunological advantages of heterologous prime-boost vaccine strategies
.
Neutralizing spike protein-specific antibodies can prevent SARS-CoV-2 infection in animal models .
These antibodies have been used as markers of protective vaccine response, although there is no exact threshold in humans
.
Although seroconversion is easier to assess, T cell responses also contribute to clearance after viral infection; these may respond more strongly to recent mutations, even in cases where there is no detectable antibody response in immunocompromised transplant recipients Down may also occur
.
Combining vaccines that mainly cause humoral reactions (for example, protein-based vaccines) and vaccines that cause strong cellular responses (for example, viral vector-based vaccines) injecting into a heterogeneous prime-boost platform may increase the risk of SARS-CoV-2 Immunity breadth
.
Animal studies have shown that a heterologous vaccine against SARS-CoV-2 can improve spike protein-specific type 1 helper T cell responses and spike protein-specific IgA antibody levels
.
Increasing evidence shows that the promoter of adenoviral vectors is safe to subsequently boost mRNA within a time interval of 6-12 weeks, and provides greater humoral and cellular immune responses than the homologous ChAd-ChAd dosage strategy
.
In the context of constant mutations, these heterologous vaccine strategies may further enhance the resistance to SARS-CoV-2 vaccination
.
.
The improved immunogenicity results also indicate that the heterologous vaccine approach can overcome the limitations of a single vaccine platform
.
The immunogenicity of adenovirus vector vaccines is limited by pre-existing neutralizing antibodies against common adenovirus serotypes in human contact, and may impair the immune response to SARS-CoV-2 spike protein
.
Extensive preclinical and early clinical studies, especially the development of human immunodeficiency virus vaccines, have long demonstrated the potential immunological advantages of heterologous prime-boost vaccine strategies
.
Neutralizing spike protein-specific antibodies can prevent SARS-CoV-2 infection in animal models .
These antibodies have been used as markers of protective vaccine response, although there is no exact threshold in humans
.
Although seroconversion is easier to assess, T cell responses also contribute to clearance after viral infection; these may respond more strongly to recent mutations, even in cases where there is no detectable antibody response in immunocompromised transplant recipients Down may also occur
.
Prevention of infection combined with vaccines that mainly cause humoral reactions (for example, protein-based vaccines) and vaccines that cause strong cellular responses (for example, viral vector-based vaccines) injection into a heterologous prime-boost platform may increase the resistance to SARS-CoV- 2.
The breadth of immunity
.
Animal studies have shown that a heterologous vaccine against SARS-CoV-2 can improve spike protein-specific type 1 helper T cell responses and spike protein-specific IgA antibody levels
.
There is growing evidence thatTherefore, the promoter of the adenoviral vector is safe to boost mRNA in a 6-12 week interval, and provides a greater humoral and cellular immune response than the homologous ChAd-ChAd dosage strategy
.
In the context of constant mutations, these heterologous vaccine strategies may further enhance the resistance to SARS-CoV-2 vaccination
.
So far, mRNA vaccines have proven to have sustained effectiveness against B.
1.
1.
7 variants, and reduced but sustained effectiveness against B.
1.
351 and P.
1 circulating variants
.
This indicates that the powerful neutralizing antibody response induced by the mRNA platform may provide the magnitude of the humoral immune response required to overcome the genetic mutations in the SARS-CoV-2 variant
.
This is in contrast to the performance of the AstraZeneca vaccine.
Although the AstraZeneca vaccine produced a strong T cell response, it did not perform well against the B.
1.
351 variant
.
In view of the continuing threat of current and future cyclic mutations, explore alternative sequence enhancement strategies (for example, viral vectors after nucleic acid platforms), complete the study of additional vaccine doses after the SARS-CoV-2 vaccine series (wild-type enhancement), wild-type primary The booster or variant dose after vaccination is under development or under development
.
In addition, the interval between prime and boost may play a key role
.
These strategies may be particularly important in enhancing the immune response of immunocompromised patients
.
1.
1.
7 variants, and reduced but sustained effectiveness against B.
1.
351 and P.
1 circulating variants
.
This indicates that the powerful neutralizing antibody response induced by the mRNA platform may provide the magnitude of the humoral immune response required to overcome the genetic mutations in the SARS-CoV-2 variant
.
This is in contrast to the performance of the AstraZeneca vaccine.
Although the AstraZeneca vaccine produced a strong T cell response, it did not perform well against the B.
1.
351 variant
.
In view of the continuing threat of current and future cyclic mutations, explore alternative sequence enhancement strategies (for example, viral vectors after nucleic acid platforms), complete the study of additional vaccine doses after the SARS-CoV-2 vaccine series (wild-type enhancement), wild-type primary The booster or variant dose after vaccination is under development or under development
.
In addition, the interval between prime and boost may play a key role
.
These strategies may be particularly important in enhancing the immune response of immunocompromised patients
.
The mixed vaccination strategy has been shown to have favorable immunogenic results as measured by the humoral and cellular responses to the original SARS-CoV-2 and its variants
.
These innovative vaccine dosage schedules may be needed to prevent interruptions in vaccine supply and maximize the immune response, which in turn will help reduce the spread of emerging variants and protect people with weakened immune systems
.
.
These innovative vaccine dosage schedules may be needed to prevent interruptions in vaccine supply and maximize the immune response, which in turn will help reduce the spread of emerging variants and protect people with weakened immune systems
.
Original source
Original source1.
Barros-Martins, J.
, Hammerschmidt, SI, Cossmann, A.
et al.
Immune responses against SARS-CoV-2 variants after heterologous and homologous ChAdOx1 nCoV-19/BNT162b2 vaccination.
Nat Med (2021).
https:/ /doi.
org/10.
1038/s41591-021-01449-9
Barros-Martins, J.
, Hammerschmidt, SI, Cossmann, A.
et al.
Nat Med https://doi.
org/10.
1038/s41591-021-01449-9
2.
Schmidt, T.
, Klemis, V.
, Schub, D.
et al.
Immunogenicity and reactogenicity of heterologous ChAdOx1 nCoV-19/mRNA vaccination.
Nat Med (2021).
https://doi.
org/10.
1038/s41591- 021-01464-w
Schmidt, T.
, Klemis, V.
, Schub, D.
et al.
Nat Med https://doi.
org/10.
1038/s41591-021-01464-w
3.
Immunogenicity and reactogenicity of BNT162b2 booster in ChAdOx1-S-primed participants (CombiVacS): a multicentre, open-label, randomised, controlled, phase 2 trial.
https:// PIIS0140-6736(21)01420-3/fulltext