Contralateral second dose improves antibody responses to a 2-dose mRNA vaccination regimen

BACKGROUNDVaccination is typically administered without regard to site of prior vaccination, but this factor may substantially affect downstream immune responses.METHODSWe assessed serological responses to initial COVID-19 vaccination in baseline seronegative adults who received second-dose boosters in the ipsilateral or contralateral arm relative to initial vaccination. We measured serum SARS-CoV-2 spike-specific Ig, receptor-binding domain-specific (RBD-specific) IgG, SARS-CoV-2 nucleocapsid-specific IgG, and neutralizing antibody titers against SARS-CoV-2.D614G (early strain) and SARS-CoV-2.B.1.1.529 (Omicron) at approximately 0.6, 8, and 14 months after boosting.RESULTSIn 947 individuals, contralateral boosting was associated with higher spike-specific serum Ig, and this effect increased over time, from a 1.1-fold to a 1.4-fold increase by 14 months (P < 0.001). A similar pattern was seen for RBD-specific IgG. Among 54 pairs matched for age, sex, and relevant time intervals, arm groups had similar antibody levels at study visit 2 (W2), but contralateral boosting resulted in significantly higher binding and neutralizing antibody titers at W3 and W4, with progressive increase over time, ranging from 1.3-fold (total Ig, P = 0.007) to 4.0-fold (pseudovirus neutralization to B.1.1.529, P < 0.001).CONCLUSIONSIn previously unexposed adults receiving an initial vaccine series with the BNT162b2 mRNA COVID-19 vaccine, contralateral boosting substantially increases antibody magnitude and breadth at times beyond 3 weeks after vaccination. This effect should be considered during arm selection in the context of multidose vaccine regimens.FUNDINGM.J. Murdock Charitable Trust, OHSU Foundation, NIH.

Vaccination before or after SARS-CoV-2 infection leads to robust humoral response and antibodies that effectively neutralize variants

Current coronavirus disease 2019 (COVID-19) vaccines effectively reduce overall morbidity and mortality and are vitally important to controlling the pandemic. Individuals who previously recovered from COVID-19 have enhanced immune responses after vaccination (hybrid immunity) compared with their naïve-vaccinated peers; however, the effects of post-vaccination breakthrough infections on humoral immune response remain to be determined. Here, we measure neutralizing antibody responses from 104 vaccinated individuals, including those with breakthrough infections, hybrid immunity, and no infection history. We find that human immune sera after breakthrough infection and vaccination after natural infection broadly neutralize SARS-CoV-2 (severe acute respiratory coronavirus 2) variants to a similar degree. Although age negatively correlates with antibody response after vaccination alone, no correlation with age was found in breakthrough or hybrid immune groups. Together, our data suggest that the additional antigen exposure from natural infection substantially boosts the quantity, quality, and breadth of humoral immune response regardless of whether it occurs before or after vaccination.

Immunogenicity of Pfizer mRNA COVID-19 vaccination followed by J&J adenovirus COVID-19 vaccination in two CLL patients

IMPORTANCE

Individuals with Chronic Lymphocytic Leukemia have significant immune disfunction, often further disrupted by treatment. While currently available COVID-19 vaccinations are highly effective in immunocompetent individuals, they are often poorly immunogenic in CLL patients. It is important to understand the role heterologous boost would have in patients who did not respond to the recommended two-dose mRNA vaccine series with a SARS-CoV-2 specific immune response.

OBJECTIVE

To characterize the immune response of two CLL patients who failed to seroconvert after initial mRNA vaccine series following a third, heterologous, COVID-19 vaccination with Ad26.COV2.S.

DESIGN

Two subjects with CLL were enrolled in an IRB-approved observational longitudinal cohort study of the immune response to COVID-19 vaccination. After enrollment, they received a third vaccination with Ad26.COV2.S. Blood was drawn prior to original vaccination series, four weeks after mRNA vaccination, and again four weeks after third vaccination.

SETTING

Eligible subjects were approached by oncologist overseeing CLL treatment and informed about study, at time of enrollment subjects consented to join the cohort study.

PARTICIPANTS

Sixteen subjects enrolled in the larger CLL cohort study, of whom two subjects received a third COVID-19 vaccination and were included in this analysis. Subject 1 is CLL treatment naive, while Subject 2 is currently on active treatment.

MAIN OUTCOMES AND MEASURES

SARS-CoV-2 specific immune response, including plasma antibodies, memory B-cells, CD4 and CD8 T-cells were assessed prior to vaccination (baseline) as well as post vaccination series and post third dose.

RESULTS

Of the two subjects who received Ad26.COV2.S doses, Subject 1 seroconverted, had RBD-specific memory B-cells as well as spike-specific CD4 T-cells while Subject 2 did not. Both subjects had a spike-specific CD8 T-cell response after original mRNA vaccination series that was further boosted after third dose (Subject 1), or remained stable (Subject 2).

CONCLUSIONS AND RELEVANCE

The results of this study, however small, is especially promising to CLL individuals who did not seroconvert following initial mRNA vaccination series. Especially those that are treatment naive, not currently in active treatment, or who may consider vaccination before beginning active treatment.