SARS-CoV-2 Omicron BA.1 variant breakthrough infections in nursing home residents after an homologous third dose of the Comirnaty® COVID-19 vaccine: Looking for correlates of protection

OBJECTIVES

We investigated whether peripheral blood levels of SARS-CoV-2 Spike (S) receptor binding domain antibodies (anti-RBD), neutralizing antibodies targeting Omicron S (NtAb), and S-reactive-IFNγ-producing CD4⁺ and CD8⁺ T cells measured after an homologous booster dose (3D) with the Comirnaty® vaccine were associated with the likelihood of subsequent breakthrough infections due to the Omicron variant.

METHODS

Observational study including 146 nursing home residents (median age, 80 years; range, 66-99; 109 female) evaluated for an immunological response after 3D (at a median of 16 days). Anti-RBD total antibodies were measured by chemiluminescent immunoassay. NtAb were quantified by an Omicron S pseudotyped virus neutralization assay. SARS-CoV-2-S specific-IFNγ-producing CD4⁺ and CD8⁺ T cells were was enumerated by whole-blood flow cytometry for intracellular cytokine staining.

RESULTS

In total, 33/146 participants contracted breakthrough Omicron infection (symptomatic in 30/33) within 4 months after 3D. Anti-RBD antibody levels were comparable in infected and uninfected participants (21,123 BAU/ml vs. 24,723 BAU/ml; P=0.34). Likewise, NtAb titers (reciprocal IC₅₀ titer, 157 vs. 95; P=0.32) and frequency of virus-reactive CD4⁺ (P=0.82) and CD8⁺ (P=0.91) T cells were similar across participant in both groups. Anti-RBD antibody levels and NtAb titers estimated at around the time of infection were also comparable (3,445 BAU/ml vs. 4,345 BAU/ml; P=0.59 and 188.5 vs. 88.9; P=0.70, respectively). Having detectable NtAb against Omicron or SARS-CoV-2-S-reactive-IFNγ-producing CD4⁺ or CD8⁺ T cells after 3D was not correlated with increased protection from breakthrough infection (OR, 1.50; P=0.54; 0.0; P=0.99 and 3.70; P=0.23, respectively).

CONCLUSION

None of the immune parameters evaluated herein, including NtAb titers against the Omicron variant, may reliably predict at the individual level the risk of contracting COVID-19 due to Omicron variant in nursing home residents. This article is protected by copyright. All rights reserved.

Neutralizing antibodies against SARS-CoV-2 variants of concern elicited by the comirnaty COVID-19 vaccine in nursing home residents

Immunosenescence may impact the functionality and breadth of vaccine-elicited humoral immune responses. The ability of sera to neutralize the SARS-CoV-2 spike protein (S) from Beta, Gamma, Delta, and Epsilon variants of concern (VOCs) relative to the ancestral Wuhan-Hu-1 strain was compared in Comirnaty COVID-19-vaccinated elderly nursing home residents, either SARS-CoV-2 naïve (n = 22) or experienced (n = 8), or SARS-CoV-2 naïve younger individuals (n = 18) and non-vaccinated individuals who recovered from severe COVID-19 (n = 19). In all groups, except that including SARS-CoV-2-experienced nursing home residents, some participants lacked NtAb against one or more VOCs, mainly the Beta variant (15–20%). Serum NtAb titers were lowest against the Beta variant followed by Gamma, Delta and Epsilon variants. Overall, fold change reduction in NtAb titers relative to the ancestral strain was greatest for the Beta variant (6.7–19.4) followed by Gamma (4.8–16.0), Epsilon (2.9–13.4), and Delta (3.5–6.5) variants, although subtle differences were observed for Beta, Epsilon and Delta variants across comparison groups. In summary, older age, frailty, and concurrence of co-morbidities had no major impact on the serum NtAb activity profile against SARS-CoV-2 VOCs.

B- and T-cell immune responses elicited by the Comirnaty® COVID-19 vaccine in nursing-home residents

Objectives

The immunogenicity of the Comirnaty® vaccine against coronavirus disease 2019 (COVID-19) has not been adequately studied in elderly people with comorbidities. We assessed antibody and T-cell responses targeted to the S protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) following full vaccination in nursing-home residents.

Methods

Sixty nursing-home residents (44 female, age 53–100 years), of whom ten had previously been diagnosed with COVID-19, and 18 healthy controls (15 female, age 27–54 years) were recruited. Pre- and post-vaccination blood specimens were available for quantification of total antibodies binding the SARS-CoV-2 S protein and for enumeration of SARS-CoV-2 S-reactive IFN-γ CD4⁺ and CD8⁺ T cells by flow cytometry.

Results

The seroconversion rate in (presumably) SARS-CoV-2-naïve nursing-home residents (41/43, 95.3%) was similar to that in controls (17/18, 94.4%). A booster effect was documented in post-vaccination samples of nursing-home residents with prior COVID-19. Plasma antibody levels were higher (p < 0.01) in recovered nursing-home residents (all 2500 IU/mL) than in individuals across the other two groups (median 1120 IU/mL in naïve nursing-home residents and 2211 IU/ml in controls). A large percentage of nursing-home residents had SARS-CoV-2 S-reactive IFN-γ CD8⁺ (naïve 31/49, 63.2%; recovered 8/10, 80%) or CD4⁺ T cells (naïve 35/49, 71.4%; recovered 7/10, 70%) at baseline, in contrast to healthy controls (3/17, 17.6% and 5/17, 29%, respectively). SARS-CoV-2 IFN-γ CD8⁺ and CD4⁺ T-cell responses were documented in 88% (15/17) and all control subjects after vaccination, respectively, but only in 65.5% (38/58) and 22.4% (13/58) of nursing-home residents. Overall, the median frequency of SARS-CoV-2 IFN-γ CD8⁺ and CD4⁺ T cells in nursing-home residents decreased in post-vaccination specimens, whereas it increased in controls.

Conclusion

The Comirnaty COVID-19 vaccine elicits robust SARS-CoV-2 S antibody responses in nursing-home residents. Nevertheless, the rate and frequency of detectable SARS-CoV-2 IFN-γ T-cell responses after vaccination was lower in nursing-home residents than in controls.

Malignant tumors of the minor salivary glands. Retrospective study on 59 cases

Minor salivary glands cancer account for 2-4% of head and neck cancer, 10% of all oral cavity cancer and 15-23% of all salivary glands cancer (1). There is a remarkable variation in clinical presentation, behavior and histology of those neoplasms. The incidence of malignancy is around 52-60% (2-4) Several classifications of salivary gland tumors have been presented, but for the present study we have utilized the WHO classification of 1992 (5). We present the results of a review of our experience with those malignancies, considering prognostic factors as histopathology, tumor grade, clinical staging, age and sex, primary location, regional and distant metastasis.