2hats
Dust.
A letter (OHSU) reporting a small study of 'breakthrough' vaccination and hybrid immunity.
26 participants (mean age 38 years, convalescents screened out) who had been vaccinated with two-dose BNT162b2 and experienced infection around 210 days after the second dose. A control cohort of BNT162b2 vaccinees with no history of infection was matched to this for comparative purposes. Convalescent vaccinee samples were taken (on average) ~1 month after infection and ~7 months after vaccination; vaccinee only samples were taken ~1 month after last dose.
The study reproduced the previously seen jump in spike RBD, IgG titres and neutralising breadth to assorted VOC (live virus assay) that has been seen in other hybrid studies. All were significantly higher than in two-dose only vaccinees. In addition they measured IgA titres and found those to be significantly higher too - indeed in the vaccinee only cohort their IgA levels were barely above the lower limit of the assay. This last result highlights how the immune response is modulated by the route of exposure to antigen (and points to, as seen in other studies, how advantageous intranasal/oral vaccines could prove to be).
Unfortunately they omitted comparative cohorts of convalescent vaccinees and a control of unvaccinated naives.
DOI: 10.1001/jama.2021.22898.
26 participants (mean age 38 years, convalescents screened out) who had been vaccinated with two-dose BNT162b2 and experienced infection around 210 days after the second dose. A control cohort of BNT162b2 vaccinees with no history of infection was matched to this for comparative purposes. Convalescent vaccinee samples were taken (on average) ~1 month after infection and ~7 months after vaccination; vaccinee only samples were taken ~1 month after last dose.
The study reproduced the previously seen jump in spike RBD, IgG titres and neutralising breadth to assorted VOC (live virus assay) that has been seen in other hybrid studies. All were significantly higher than in two-dose only vaccinees. In addition they measured IgA titres and found those to be significantly higher too - indeed in the vaccinee only cohort their IgA levels were barely above the lower limit of the assay. This last result highlights how the immune response is modulated by the route of exposure to antigen (and points to, as seen in other studies, how advantageous intranasal/oral vaccines could prove to be).
Unfortunately they omitted comparative cohorts of convalescent vaccinees and a control of unvaccinated naives.
DOI: 10.1001/jama.2021.22898.
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