Immunogenicity of bivalent omicron (BA.1) booster vaccination after different priming regimens in health-care workers in the Netherlands (SWITCH ON): results from the direct boost group of an open-label, multicentre, randomised controlled trial.

BACKGROUND: Bivalent mRNA-based COVID-19 vaccines encoding the ancestral and omicron spike (S) protein were developed as a countermeasure against antigenically distinct SARS-CoV-2 variants. We aimed to assess the (variant-specific) immunogenicity and reactogenicity of mRNA-based bivalent omicron (BA.1) vaccines in individuals who were primed with adenovirus-based or mRNA-based vaccines encoding the ancestral spike protein. METHODS: We analysed results of the direct boost group of the SWITCH ON study, an open-label, multicentre, randomised controlled trial. Health-care workers from four academic hospitals in the Netherlands aged 18-65 years who had completed a primary COVID-19 vaccination regimen and received one booster of an mRNA-based vaccine, given no later than 3 months previously, were eligible. Participants were randomly assigned (1:1) using computer software in block sizes of 16 and 24 to receive an omicron BA.1 bivalent booster straight away (direct boost group) or a bivalent omicron BA.5 booster, postponed for 90 days (postponed boost group), stratified by priming regimen. The BNT162b2 OMI BA.1 boost was given to participants younger than 45 years, and the mRNA-1273.214 boost was given to participants 45 years or older, as per Dutch guidelines. The direct boost group, whose results are presented here, were divided into four subgroups for analysis: (1) Ad26.COV2.S (Johnson & Johnson) prime and BNT162b2 OMI BA.1 (BioNTech-Pfizer) boost (Ad/P), (2) mRNA-based prime and BNT162b2 OMI BA.1 boost (mRNA/P), (3) Ad26.COV2.S prime and mRNA-1273.214 (Moderna) boost (Ad/M), and (4) mRNA-based prime and mRNA-1273.214 boost (mRNA/M). The primary outcome was fold change in S protein S1 subunit-specific IgG antibodies before and 28 days after booster vaccination. The primary outcome and safety were assessed in all participants except those who withdrew, had a SARS-CoV-2 breakthrough infection, or had a missing blood sample at day 0 or day 28. This trial is registered with ClinicalTrials.gov, NCT05471440. FINDINGS: Between Sept 2 and Oct 4, 2022, 219 (50%) of 434 eligible participants were randomly assigned to the direct boost group; 187 participants were included in the primary analyses; exclusions were mainly due to SARS-CoV-2 infection between days 0 and 28. From the 187 included participants, 138 (74%) were female and 49 (26%) were male. 42 (22%) of 187 participants received Ad/P and 44 (24%) mRNA/P (those aged <45 years), and 45 (24%) had received Ad/M and 56 (30%) mRNA/M (those aged ≥45 years). S1-specific binding antibody concentrations increased 7 days after bivalent booster vaccination and remained stable over 28 days in all four subgroups (geometric mean ratio [GMR] between day 0 and day 28 was 1·15 [95% CI 1·12-1·19] for the Ad/P group, 1·17 [1·14-1·20] for the mRNA/P group, 1·20 [1·17-1·23] for the Ad/M group, and 1·16 [1·13-1·19] for the mRNA/M group). We observed no significant difference in the GMR between the Ad/P and mRNA/P groups (p=0·51). The GMR appeared to be higher in the Ad/M group than in the mRNA/M group, but was not significant (p=0·073). Most side-effects were mild to moderate in severity and resolved within 48 h in most individuals. INTERPRETATION: Booster vaccination with mRNA-1273.214 or BNT162b2 OMI BA.1 in adult healthcare workers resulted in a rapid recall of humoral and cellular immune responses independent of the priming regimen. Monitoring of SARS-CoV-2 immunity at the population level, and simultaneously antigenic drift at the virus level, remains crucial to assess the necessity and timing of COVID-19 variant-specific booster vaccinations. FUNDING: The Netherlands Organization for Health Research and Development (ZonMw).

Durability of immune responses after boosting in Ad26.COV2.S-primed healthcare workers.

The emergence of SARS-CoV-2 variants raised questions regarding the durability of immune responses after homologous or heterologous booster vaccination after Ad26.COV2.S priming. We found that SARS-CoV-2-specific binding antibodies, neutralizing antibodies and T-cells are detectable 5 months after boosting, although waning of antibodies and limited cross-reactivity with Omicron BA.1 was observed.

Analyzing the immunogenicity of bivalent booster vaccinations in healthcare workers: The SWITCH ON trial protocol.

Vaccination against coronavirus disease 2019 (COVID-19) has contributed greatly to providing protection against severe disease, thereby reducing hospital admissions and deaths. Several studies have reported reduction in vaccine effectiveness over time against the Omicron sub-lineages. However, the willingness to receive regular booster doses in the general population is declining. To determine the need for repeated booster vaccinations in healthy individuals and to aid policymakers in future public health interventions for COVID-19, we aim to gain insight into the immunogenicity of the additional bivalent booster vaccination in a representative sample of the healthy Dutch population. The SWITCH ON study was initiated to investigate three main topics: i) immunogenicity of bivalent vaccines after priming with adenovirus- or mRNA-based vaccines, ii) immunological recall responses and reactivity with relevant variants after booster vaccination, and iii) the necessity of booster vaccinations for the healthy population in the future. Clinical trial registration: https://clinicaltrials.gov/, identifier NCT05471440.

Ad26.COV2.S priming provided a solid immunological base for mRNA-based COVID-19 booster vaccination.

The emergence of novel SARS-CoV-2 variants led to the recommendation of booster vaccinations after Ad26.COV2.S priming. It was previously shown that heterologous booster vaccination induces high antibody levels, but how heterologous boosters affect other functional aspects of the immune response remained unknown. Here, we performed immunological profiling of Ad26.COV2.S-primed individuals before and after homologous or heterologous (mRNA-1273 or BNT162b2) booster. Booster vaccinations increased functional antibodies targeting ancestral SARS-CoV-2 and emerging variants. Especially heterologous booster vaccinations induced high levels of functional antibodies. In contrast, T-cell responses were similar in magnitude following homologous or heterologous booster vaccination and retained cross-reactivity towards variants. Booster vaccination led to a minimal expansion of SARS-CoV-2-specific T-cell clones and no increase in the breadth of the T-cell repertoire. In conclusion, we show that Ad26.COV2.S priming vaccination provided a solid immunological base for heterologous boosting, increasing humoral and cellular responses targeting emerging variants of concern.

Immunogenicity and Reactogenicity of Vaccine Boosters after Ad26.COV2.S Priming.

BACKGROUND: The Ad26.COV2.S vaccine, which was approved as a single-shot immunization regimen, has been shown to be effective against severe coronavirus disease 2019. However, this vaccine induces lower severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein (S)-specific antibody levels than those induced by messenger RNA (mRNA)-based vaccines. The immunogenicity and reactogenicity of a homologous or heterologous booster in persons who have received an Ad26.COV2.S priming dose are unclear. METHODS: In this single-blind, multicenter, randomized, controlled trial involving health care workers who had received a priming dose of Ad26.COV2.S vaccine, we assessed immunogenicity and reactogenicity 28 days after a homologous or heterologous booster vaccination. The participants were assigned to receive no booster, an Ad26.COV2.S booster, an mRNA-1273 booster, or a BNT162b2 booster. The primary end point was the level of S-specific binding antibodies, and the secondary end points were the levels of neutralizing antibodies, S-specific T-cell responses, and reactogenicity. A post hoc analysis was performed to compare mRNA-1273 boosting with BNT162b2 boosting. RESULTS: Homologous or heterologous booster vaccination resulted in higher levels of S-specific binding antibodies, neutralizing antibodies, and T-cell responses than a single Ad26.COV2.S vaccination. The increase in binding antibodies was significantly larger with heterologous regimens that included mRNA-based vaccines than with the homologous booster. The mRNA-1273 booster was most immunogenic and was associated with higher reactogenicity than the BNT162b2 and Ad26.COV2.S boosters. Local and systemic reactions were generally mild to moderate in the first 2 days after booster administration. CONCLUSIONS: The Ad26.COV2.S and mRNA boosters had an acceptable safety profile and were immunogenic in health care workers who had received a priming dose of Ad26.COV2.S vaccine. The strongest responses occurred after boosting with mRNA-based vaccines. Boosting with any available vaccine was better than not boosting. (Funded by the Netherlands Organization for Health Research and Development ZonMw; SWITCH ClinicalTrials.gov number, NCT04927936.).

Association between Clinical Frailty Scale score and hospital mortality in adult patients with COVID-19 (COMET): an international, multicentre, retrospective, observational cohort study.

BACKGROUND: During the COVID-19 pandemic, the scarcity of resources has necessitated triage of critical care for patients with the disease. In patients aged 65 years and older, triage decisions are regularly based on degree of frailty measured by the Clinical Frailty Scale (CFS). However, the CFS could also be useful in patients younger than 65 years. We aimed to examine the association between CFS score and hospital mortality and between CFS score and admission to intensive care in adult patients of all ages with COVID-19 across Europe. METHODS: This analysis was part of the COVID Medication (COMET) study, an international, multicentre, retrospective observational cohort study in 63 hospitals in 11 countries in Europe. Eligible patients were aged 18 years and older, had been admitted to hospital, and either tested positive by PCR for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or were judged to have a high clinical likelihood of having SARS-CoV-2 infection by the local COVID-19 expert team. CFS was used to assess level of frailty: fit (CFS1-3), mildly frail (CFS4-5), or frail (CFS6-9). The primary outcome was hospital mortality. The secondary outcome was admission to intensive care. Data were analysed using a multivariable binary logistic regression model adjusted for covariates (age, sex, number of drugs prescribed, and type of drug class as a proxy for comorbidities). FINDINGS: Between March 30 and July 15, 2020, 2434 patients (median age 68 years [IQR 55-77]; 1480 [61%] men, 954 [30%] women) had CFS scores available and were included in the analyses. In the total sample and in patients aged 65 years and older, frail patients and mildly frail patients had a significantly higher risk of hospital mortality than fit patients (total sample: CFS6-9 vs CFS1-3 odds ratio [OR] 2·71 [95% CI 2·04-3·60], p<0·0001 and CFS4-5 vs CFS1-3 OR 1·54 [1·16-2·06], p=0·0030; age ≥65 years: CFS6-9 vs CFS1-3 OR 2·90 [2·12-3·97], p<0·0001 and CFS4-5 vs CFS1-3 OR 1·64 [1·20-2·25], p=0·0020). In patients younger than 65 years, an increased hospital mortality risk was only observed in frail patients (CFS6-9 vs CFS1-3 OR 2·22 [1·08-4·57], p=0·030; CFS4-5 vs CFS1-3 OR 1·08 [0·48-2·39], p=0·86). Frail patients had a higher incidence of admission to intensive care than fit patients (CFS6-9 vs CFS1-3 OR 1·54 [1·21-1·97], p=0·0010), whereas mildly frail patients had a lower incidence than fit patients (CFS4-5 vs CFS1-3 OR 0·71 [0·55-0·92], p=0·0090). Among patients younger than 65 years, frail patients had an increased incidence of admission to intensive care (CFS6-9 vs CFS1-3 OR 2·96 [1·98-4·43], p<0·0001), whereas mildly frail patients had no significant difference in incidence compared with fit patients (CFS4-5 vs CFS1-3 OR 0·93 [0·63-1·38], p=0·72). Among patients aged 65 years and older, frail patients had no significant difference in the incidence of admission to intensive care compared with fit patients (CFS6-9 vs CFS1-3 OR 1·27 [0·92-1·75], p=0·14), whereas mildly frail patients had a lower incidence than fit patients (CFS4-5 vs CFS1-3 OR 0·66 [0·47-0·93], p=0·018). INTERPRETATION: The results of this study suggest that CFS score is a suitable risk marker for hospital mortality in adult patients with COVID-19. However, treatment decisions based on the CFS in patients younger than 65 years should be made with caution. FUNDING: LOEY Foundation.

No association between use of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers prior to hospital admission and clinical course of COVID-19 in the COvid MEdicaTion (COMET) study.

Since the outbreak of SARS-CoV-2, also known as COVID-19, conflicting theories have circulated on the influence of angiotensin-converting enzyme inhibitors (ACEi) and angiotensin II receptor blockers (ARB) on incidence and clinical course of COVID-19, but data are scarce. The COvid MEdicaTion (COMET) study is an observational, multinational study that focused on the clinical course of COVID-19 (i.e. hospital mortality and intensive care unit [ICU] admission), and included COVID-19 patients who were registered at the emergency department or admitted to clinical wards of 63 participating hospitals. Pharmacists, clinical pharmacologists or treating physicians collected data on medication prescribed prior to admission. The association between the medication and composite clinical endpoint, including mortality and ICU admission, was analysed by multivariable logistic regression models to adjust for potential confounders. A total of 4870 patients were enrolled. ACEi were used by 847 (17.4%) patients and ARB by 761 (15.6%) patients. No significant association was seen with ACEi and the composite endpoint (adjusted odds ratio [OR] 0.94; 95% confidence interval [CI] 0.79 to 1.12), mortality (OR 1.03; 95%CI 0.84 to 1.27) or ICU admission (OR 0.96; 95%CI 0.78 to 1.19) after adjustment for covariates. Similarly, no association was observed between ARB and the composite endpoint (OR 1.09; 95%CI 0.90 to 1.30), mortality (OR 1.12; OR 0.90 to 1.39) or ICU admission (OR 1.21; 95%CI 0.98 to 1.49). In conclusion, we found no evidence of a harmful or beneficial effect of ACEi or ARB use prior to hospital admission on ICU admission or hospital mortality.

COvid MEdicaTion (COMET) study: protocol for a cohort study.

Various theories about drugs such as ACE inhibitors or angiotensin II receptor blockers (ARBs) in relation to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and clinical outcomes of COVID-19 are circulating in both mainstream media and medical literature. These are based on the fact that ACE2 facilitates SARS-CoV-2 cell invasion via binding of a viral spike protein to ACE2. However, the effect of ACE inhibitors, ARBs and other drugs on ACE2 is unclear and all theories are based on conflicting evidence mainly from animal studies. Therefore, clinical evidence is urgently needed. The aim of this study is to investigate the relationship between use of these drugs on clinical outcome of patients with COVID-19. Patients will be included from several hospitals in Europe. Data will be collected in a user-friendly database (Digitalis) on an external server. Analyses will be adjusted for sex, age and presence of cardiovascular disease, hypertension and diabetes. These results will enable more rational choices for randomised controlled trials for preventive and therapeutic strategies in COVID-19.