Humoral Responses Against Variants of Concern by COVID-19 mRNA Vaccines in Immunocompromised Patients

Importance

There are limited comparative data on the durability of neutralizing antibody (nAb) responses elicited by messenger RNA (mRNA) vaccines against the SARS-CoV-2 variants of concern (VOCs) in immunocompromised patients and healthy controls.

Objective

To assess the humoral responses after vaccination with BNT162b2 (Pfizer-BioNTech) or mRNA-1273 (Moderna) vaccines.

Design, Setting, and Participants

In this prospective, longitudinal monocentric comparative effectiveness study conducted at the Lausanne University Hospital, binding IgG anti-spike antibody and nAb levels were measured at 1 week, 1 month, 3 months, and 6 months after vaccination with mRNA-1273 (24.6% of participants) or BNT162b2 (75.3% of participants).

Interventions

All participants received 2 doses of either mRNA-1273 or BNT162b2 vaccines 4 to 6 weeks apart.

Main Outcomes and Measures

The primary outcome of the study was the persistence of nAb responses against the original, nonvariant SARS-CoV-2 (2019-nCoV) and different VOCs at 6 months after vaccination. Key secondary outcomes were associations of the type of mRNA vaccine, the underlying disease, and the treatment with the response to vaccination.

Results

Among the 841 participants enrolled between January 14 and August 8, 2021, the patient population comprised 637 participants (mean [SD] age, 61.8 [13.7] years; 386 [60.6%] female), and the healthy control population comprised 204 participants (mean [SD] age, 45.9 [12.0] years; 144 [70.6%] female). There were 399 patients with solid cancers, 101 with hematologic cancers, 38 with solid organ transplants, 99 with autoimmune diseases, and 204 healthy controls. More than 15 000 nAb determinations were performed against the original, nonvariant 2019-nCoV and the Alpha, Beta, Gamma, and Delta variants. The proportions of nAbs and their titers decreased in all study groups at 6 months after vaccination, with the greatest decreases for the Beta and Delta variants. For Beta, the proportion decreased to a median (SE) of 39.2% (5.5%) in those with hematologic cancers, 44.8% (2.7%) in those with solid cancers, 23.1% (8.3%) in those with solid organ transplants, and 22.7% (4.8%) in those with autoimmune diseases compared with 52.1% (4.2%) in healthy controls. For Delta, the proportions decreased to 41.8% (5.6%) in participants with hematologic cancer, 51.9% (2.7%) in those with solid cancers, 26.9% (8.7%) in those with solid organ transplants, and 30.7% (5.3%) in those with autoimmune diseases compared with 56.9% (4.1%) healthy controls. Neutralizing antibody titers decreased 3.5- to 5-fold between month 1 and month 6, and the estimated duration of response was greater and more durable among those participants vaccinated with mRNA-1273. In participants with solid cancers, the estimated duration of nAbs against the Beta variant was 221 days with mRNA-1273 and 146 days with BNT162b2, and against the Delta variant, it was 226 days with mRNA-1273 and 161 with BNT162b2. The estimated duration of nAbs in participants with hematologic cancers was 113 and 127 days against Beta and Delta variants, respectively.

Conclusions and Relevance

This comparative effectiveness study suggests that approximately half of patients with hematologic cancers and solid cancers, about 70% of patients with solid organ transplants or autoimmune diseases, and 40% of healthy controls have lost nAbs against the circulating VOCs at 6 months after vaccination. These findings may be helpful for developing the best boosting vaccination schedule especially in immunocompromised patients.

Cuffless systolic and diastolic blood pressure estimation at the wrist via an optical device: comparison to intra-arterial measurements

 

The diagnosis and management of hypertension usually requires the estimation of blood pressure (BP) by means of an inflatable cuff. This procedure generates discomfort and limits patient compliance. Cuffless devices capture BP readings without performing any arterial occlusion. We believe that comfortable and cuffless BP monitoring devices can significantly aid in the fight against hypertension and support the expansion of ambulatory and remote patient monitoring programs, provided that these devices provide reliable BP readings.

The purpose of this study was to compare the systolic (S) and diastolic (D) blood pressure (BP) estimations from a new optical device at the wrist (figure) against invasive measurements performed on patients scheduled for radial arterial catheterization. The first results from this study were recently published and demonstrated good agreement for the overall study population. Here we report expanded statistical analyses for different population subgroups such as gender, age, body mass index (BMI) and skin color.

The study protocol consisted of the simultaneous recording of reflective photo-plethysmographic signals (PPG) from the optical device, and BP values recorded by a contralateral radial arterial catheter. The PPG signals were processed to generate estimates of SBP and DBP. Agreement of paired BP estimations was further calculated in terms of standard deviation (SD) of differences. The mean of differences were systematically zero because BP estimations from the optical device were calibrated for each patient.

The table shows that, for the overall population, both SBP and DBP differences SDs were smaller than 8 mmHg (as already published). Furthermore, across different population groups, both genders, all BMIs and all skin colors also resulted in SDs smaller than 8 mmHg. Only patients whose age was above 65 years were associated with a higher SD.

For the overall population and most subgroups the new optical technique appears to be capable of replacing more traditional methods of BP estimation. Only the SBP differences for the subgroup of older patients were larger. Additional studies are needed to confirm and expand these very encouraging results.

Table 1. SD of measured BP differences Population N SD of SBP differences SD of DBP differences (mmHg) (mmHg) All 16 7.1 2.9 Gender Male 10 6.4 2.8 Female 6 8.0 3.1 Age (years) <65 7 4.0 2.3 >65 9 *9.3 3.4 BMI (kg/m2) <26 10 7.9 2.9 >26 6 5.7 2.8 Skin Color (Fitzpatrick) 2 13 7.7 3.0 3 3 4.5 2.6 *Only subgroup with a SD larger than 8mmHg.

Figure 1. The investigational device

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Aktiia SA

CD4+CD25+ T cell depletion impairs tolerance induction in a murine model of asthma

BACKGROUND

Regulatory T cells (Tregs) are key players in controlling the development of airway inflammation. However, their role in the mechanisms leading to tolerance in established allergic asthma is unclear.

OBJECTIVE

To examine the role of Tregs in tolerance induction in a murine model of asthma.

METHODS

Ovalbumin (OVA) sensitized asthmatic mice were depleted or not of CD25(+) T cells by anti-CD25 PC61 monoclonal antibody (mAb) before intranasal treatment (INT) with OVA, then challenged with OVA aerosol. To further evaluate the respective regulatory activity of CD4(+)CD25(+) and CD4(+)CD25(-) T cells, both T cell subsets were transferred from tolerized or non-tolerized animals to asthmatic recipients. Bronchoalveolar lavage fluid (BALF), T cell proliferation and cytokine secretion were examined.

RESULTS

Intranasal treatment with OVA led to increased levels of IL-10, TGF-beta and IL-17 in lung homogenates, inhibition of eosinophil recruitment into the BALF and antigen specific T cell hyporesponsiveness. CD4(+)CD25(+)Foxp3(+) T cells were markedly upregulated in lungs and suppressed in vitro and in vivo OVA-specific T cell responses. Depletion of CD25(+) cells before OVA INT severely hampered tolerance induction as indicated by a strong recruitment of eosinophils into BALF and a vigorous T cell response to OVA upon challenge. However, the transfer of CD4(+)CD25(-) T cells not only suppressed antigen specific T cell responsiveness but also significantly reduced eosinophil recruitment as opposed to CD4(+)CD25(+) T cells. As compared with control mice, a significantly higher proportion of CD4(+)CD25(-) T cells from OVA treated mice expressed mTGF-beta.

CONCLUSION

Both CD4(+)CD25(+) and CD4(+)CD25(-) T cells appear to be essential to tolerance induction. The relationship between both subsets and the mechanisms of their regulatory activity will have to be further analyzed.