Prof Penny Moore's (South African Research Chair, Virus-Host Dynamics - University of the Witwatersrand) research has shown that people who have been infected with the coronavirus variant responsible for 98% of SA's Covid-19 cases have antibodies that fend off all variants.
This suggests vaccines might offer protection against all variants of the virus — even those that have not yet evolved. Her team analysed antibodies from the so-called B. 1.351 infection. They do not know yet why the B. 1.351 infection results in a such a broad immune response, but she hopes to find out.
Her team used a ‘pseudovirus’ — a modified form of HIV that infects cells using the Covid spike protein — to measure the capacity of the antibodies to block infection. The antibodies of people who recovered from B.1.351 infection did a good job of blocking pseudoviruses with B.1.351 mutations.
To Moore’s surprise, the antibodies also blocked other strains. These included some that were similar to the ones that B.1.351 displaced, and an immune-evading variant called P.1, identified in Brazil.
Last week Moderna updated the versions of their vaccine, based on the genetic sequence of the B.1.351 variant - and went ahead to the trial stage. There's a strong possibility that these updated vaccines will perform a bit better.
PS: The following is an extract of the Abstract of a latest preprint of Penny's team if anyone is interested to read.
"Neutralization escape by SARS-CoV-2 variants, as has been observed in the 501Y.V2 (B.1.351) variant, has impacted the efficacy of first generation COVID-19 vaccines. Here, the antibody response to the 501Y.V2 variant was examined in a cohort of patients hospitalized with COVID-19 in early 2021 - when over 90% of infections in South Africa were attributed to 501Y.V2. Robust binding and neutralizing antibody titers to the 501Y.V2 variant were detected and these binding antibodies showed high levels of cross-reactivity for the original variant, from the first wave. In contrast to an earlier study where sera from individuals infected with the original variant showed dramatically reduced potency against 501Y.V2, sera from 501Y.V2-infected patients maintained good cross-reactivity against viruses from the first wave. Furthermore, sera from 501Y.V2-infected patients also neutralized the 501Y.V3 (P.1) variant first described in Brazil, and now circulating globally. Collectively these data suggest that the antibody response in patients infected with 501Y.V2 has a broad specificity and that vaccines designed with the 501Y.V2 sequence may elicit more cross-reactive responses."
This suggests vaccines might offer protection against all variants of the virus — even those that have not yet evolved. Her team analysed antibodies from the so-called B. 1.351 infection. They do not know yet why the B. 1.351 infection results in a such a broad immune response, but she hopes to find out.
Her team used a ‘pseudovirus’ — a modified form of HIV that infects cells using the Covid spike protein — to measure the capacity of the antibodies to block infection. The antibodies of people who recovered from B.1.351 infection did a good job of blocking pseudoviruses with B.1.351 mutations.
To Moore’s surprise, the antibodies also blocked other strains. These included some that were similar to the ones that B.1.351 displaced, and an immune-evading variant called P.1, identified in Brazil.
Last week Moderna updated the versions of their vaccine, based on the genetic sequence of the B.1.351 variant - and went ahead to the trial stage. There's a strong possibility that these updated vaccines will perform a bit better.
PS: The following is an extract of the Abstract of a latest preprint of Penny's team if anyone is interested to read.
"Neutralization escape by SARS-CoV-2 variants, as has been observed in the 501Y.V2 (B.1.351) variant, has impacted the efficacy of first generation COVID-19 vaccines. Here, the antibody response to the 501Y.V2 variant was examined in a cohort of patients hospitalized with COVID-19 in early 2021 - when over 90% of infections in South Africa were attributed to 501Y.V2. Robust binding and neutralizing antibody titers to the 501Y.V2 variant were detected and these binding antibodies showed high levels of cross-reactivity for the original variant, from the first wave. In contrast to an earlier study where sera from individuals infected with the original variant showed dramatically reduced potency against 501Y.V2, sera from 501Y.V2-infected patients maintained good cross-reactivity against viruses from the first wave. Furthermore, sera from 501Y.V2-infected patients also neutralized the 501Y.V3 (P.1) variant first described in Brazil, and now circulating globally. Collectively these data suggest that the antibody response in patients infected with 501Y.V2 has a broad specificity and that vaccines designed with the 501Y.V2 sequence may elicit more cross-reactive responses."
