In a cohort of BNT162b2 (Pfizer–BioNTech) mRNA vaccine recipients (n = 1,090), we observed that spike-specific IgG antibody levels and ACE2 antibody binding inhibition responses elicited by a single vaccine dose in individuals with prior SARS-CoV-2 infection (n = 35) were similar to those seen after two doses of vaccine in individuals without prior infection (n = 228). Post-vaccine symptoms were more prominent for those with prior infection after the first dose, but symptomology was similar between groups after the second dose.

C urrently, 3 vaccines have been granted Emergency Use Authorization for coronavirus disease 2019 prevention in the United States. These include the messenger RNA (mRNA) platform vaccines (mRNA-1273; Moderna/National Institutes of Health) and BNT162b2 (Pfizer-BioNTech) and an adenovirus vector vaccine (Ad26.CoV2.S; Johnson & Johnson), which were 94%, 95%, and 67% effective against COVID-19 infection in their phase III registry trials against the endemic variants at the time, respectively. 1-3 All 3 vaccines target the viral spike (S) protein that facilitates severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry into host cells via its receptor binding domain, which interacts with angiotensin-converting enzyme 2. 4 Although the mRNA platform vaccines are 2-dose vaccines administered 3-4 weeks apart, the Ad26.CoV2.S is administered as a single dose. Another adenovirus vector vaccine (ChAdOx1; Astrazeneca), not yet authorized in the United States, is intended as a 2-dose regimen with an interval of 8-12 weeks.Patients with inflammatory bowel disease (IBD) on corticosteroids, immunomodulators, and advanced therapies may have normal to slightly decreased humoral responses to the SARS-CoV-2 mRNA vaccine platforms. 1 In addition, patients receiving infliximab and/or thiopurines have significantly lower rates of seroconversion than those on vedolizumab monotherapy after a single dose of either BNT162b2 or ChAdOx1. 2 A study of solid organ transplant recipients showed decreased humoral responses to Ad26.CoV2.S vaccine relative to both mRNA platform vaccines, although it is unknown whether these findings are generalizable to other immune compromised populations. 5 Q5 We aimed to assess for differences in serologic responses among patients with IBD who received Ad26.CoV2.S relative to those receiving mRNA-1273 or BNT162b2. Among 353 vaccine recipients with IBD participating in a prospective SARS-CoV-2 vaccine registry without prior COVID-19 infection and who had completed a full vaccine regimen, 148 (42%), 193 (55%), and 12 (3%) received mRNA-1273, BNT162b2, and Ad26.CoV2.S, respectively. Demographic and disease characteristics were similar across vaccine groups (mean age, 51 years, 62% were female) (Supplementary Table 1). Approximately 290 (83.1%) participants were on immune-modifying therapies (IMTs), as defined by receipt of advanced therapies (biologics or JAK inhibitors, 80.2%), immunomodulators (16.6%), and/or systemic corticosteroids (6.6%) at the time of initial vaccination. At least 2 weeks after completion of the vaccine regimen, positive antibody levels were detected in 121 (100%), 142 (99%), and 9 (90%) patients receiving mRNA-1273, BNT162b2, and Ad26.CoV2.S, respectively (Figure 1A). Quantitative log 10 (anti-Spike IgG

Longitudinal studies of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine-induced immune responses in patients with cancer are needed to optimize clinical care. In a prospective cohort study of 366 (291 vaccinated) patients, we measured antibody levels [anti-spike (IgG-(S-RBD) and anti-nucleocapsid immunoglobulin] at three time points. Antibody level trajectories and frequency of breakthrough infections were evaluated by tumor type and timing of treatment relative to vaccination. IgG-(S-RBD) at peak response (median = 42 days after dose 2) was higher (P = 0.002) and remained higher after 4 to 6 months (P = 0.003) in patients receiving mRNA-1273 compared with BNT162b2. Patients with solid tumors attained higher peak levels (P = 0.001) and sustained levels after 4 to 6 months (P < 0.001) compared with those with hematologic malignancies. B-cell targeted treatment reduced peak (P = 0.001) and sustained antibody responses (P = 0.003). Solid tumor patients receiving immune checkpoint inhibitors before vaccination had lower sustained antibody levels than those who received treatment after vaccination (P = 0.043). Two (0.69%) vaccinated and one (1.9%) unvaccinated patient had severe COVID-19 illness during follow-up. Our study shows variation in sustained antibody responses across cancer populations receiving various therapeutic modalities, with important implications for vaccine booster timing and patient selection. Significance: Long-term studies of immunogenicity of SARS-CoV-2 vaccines in patients with cancer are needed to inform evidence-based guidelines for booster vaccinations and to tailor sequence and timing of vaccinations to elicit improved humoral responses.

ImportanceSome individuals who were infected by the SARS-CoV-2 Omicron variant may have been completely unaware of their infectious status while the virus was actively transmissible.ObjectiveTo examine awareness of infectious status among individuals during the recent Omicron variant surge in a diverse and populous urban region of Los Angeles County.Design, Setting, and ParticipantsThis cohort study analyzed the records of adult employees and patients of an academic medical center who were enrolled in a longitudinal COVID-19 serological study in Los Angeles County, California. These participants had 2 or more serial anti-nucleocapsid IgG (IgG-N) antibody measurements at least 1 month apart, with the first occurring after the end of a regional Delta variant surge (September 15, 2021) and a subsequent one occurring after the start of a regional Omicron variant surge (December 15, 2021). Adults with evidence of new SARS-CoV-2 infection occurring during the Omicron variant surge period through May 4, 2022, were included in the present study sample.ExposuresRecent Omicron variant infection as evidenced by SARS-CoV-2 seroconversion.Main Outcomes and MeasuresAwareness of recent SARS-CoV-2 infection was ascertained from review of self-reported health updates, medical records, and COVID-19 testing data.ResultsOf the 210 participants (median [range] age, 51 (23-84) years; 136 women [65%]) with serological evidence of recent Omicron variant infection, 44% (92) demonstrated awareness of any recent Omicron variant infection and 56% (118) reported being unaware of their infectious status. Among those who were unaware, 10% (12 of 118) reported having had any symptoms, which they attributed to a common cold or other non–SARS-CoV-2 infection. In multivariable analyses that accounted for demographic and clinical characteristics, participants who were health care employees of the medical center were more likely than nonemployees to be aware of their recent Omicron variant infection (adjusted odds ratio, 2.46; 95% CI, 1.30-4.65).Conclusions and RelevanceResults of this study suggest that more than half of adults with recent Omicron variant infection were unaware of their infectious status and that awareness was higher among health care employees than nonemployees, yet still low overall. Unawareness may be a highly prevalent factor associated with rapid person-to-person transmission within communities.

These data indicate that the automated, microparticle-based chemiluminescent HCV core antigen assay can reduce the window period for detection of potentially infected blood donors by 32.7 days, and it represents a viable alternative to HCV RNA testing.