Longitudinal Humoral and Cell-Mediated Immune Responses in a Population-Based Cohort in Zurich, Switzerland from March to June 2022 - Evidence for Protection against Omicron SARS-CoV-2 Infection by Neutralizing Antibodies and Spike-specific T cells

BACKGROUND

The correlate(s) of protection against SARS-CoV-2 remain incompletely defined. Additional information regarding the combinations of antibody and T cell-mediated immunity which can protect against (re)infection are needed.

METHODS

We conducted a population-based, longitudinal cohort study including 1044 individuals of varying SARS-CoV-2 vaccination and infection statuses. We assessed Spike (S)- and Nucleocapsid (N)-IgG and wildtype, delta, and omicron neutralizing antibody (N-Ab) activity. In a subset of 328 individuals, we evaluated S, Membrane (M) and N-specific T cells. 3 months later, we reassessed antibody (n=964) and T cell (n=141) responses and evaluated factors associated with protection from (re)infection.

RESULTS

At study start, >98% of participants were S-IgG seropositive. N-IgG and M/N-T cell responses increased over time, indicating viral (re)exposure, despite existing S-IgG. Compared to N-IgG, M/N-T cells were a more sensitive measure of viral exposure. High N-IgG titers, omicron-N-Ab activity, and S-specific-T cell responses were all associated with reduced likelihood of (re)infection over time.

CONCLUSIONS

Population-level SARS-CoV-2 immunity is S-IgG-dominated, but heterogenous. M/N T cell responses can distinguish previous infection from vaccination, and monitoring a combination of N-IgG, omicron-N-Ab and S-T cell responses may help estimate protection against SARS-CoV-2 (re)infection.

Participation, retention and uptake in a multicentre pre-exposure prophylaxis cohort using online, smartphone-compatible data collection

Objectives

The aim of the study was to assess the feasibility of a national pre‐exposure prophylaxis (PrEP) programme using smartphone‐compatible data collection.

Methods

This was a multicentre cohort study (NCT03893188) enrolling individuals interested in PrEP in Switzerland. All centres participate in the SwissPrEPared programme, which uses smartphone‐compatible data collection. Feasibility was assessed after centres had enrolled at least one participant. Participants were HIV‐negative individuals presenting for PrEP counselling. Outcomes were participation (number enrolled/number eligible), enrolment rates (number enrolled per month), retention at first follow‐up (number with first follow‐up/number enrolled), and uptake (proportion attending first visit as scheduled). Participant characteristics were compared between those retained after baseline assessment and those who dropped out.

Results

Between April 2019 and January 2020, 987 individuals were assessed for eligibility, of whom 969 were enrolled (participation: 98.2%). The median enrolment rate was 86 per month [interquartile range (IQR) 52–137]. Retention at first follow‐up and uptake were both 80.7% (782/969 and 532/659, respectively). At enrolment, the median age was 40 (IQR 33–47) years, 95% were men who have sex with men, 47% had a university degree, and 75.5% were already taking PrEP. Most reported multiple casual partners (89.2%), previous sexually transmitted infections (74%) and sexualized drug use (73.1%). At baseline, 25.5% tested positive for either syphilis, gonorrhoea or chlamydia. Participants who dropped out were at lower risk of HIV infection than those retained after baseline assessment.

Conclusions

In a national PrEP programme using smartphone‐compatible data collection, participation, retention and uptake were high. Participants retained after baseline assessment were at considerable risk of HIV infection. Younger, less educated individuals were underrepresented in the SwissPrEPared cohort.

Hyperglycaemia and pharmacokinetics of rifampicin/isoniazid among TB-HIV co-infected patients in Kampala, Uganda

OBJECTIVE: 1) To determine the prevalence of diabetes mellitus and impaired fasting glucose (IFG) in patients with TB and HIV co-infection, and 2) to investigate the effect of fasting plasma glucose (FPG) on rifampicin (RIF) and isoniazid (INH) serum concentrations.DESIGN: Retrospective data analysis of a cohort of HIV-infected adults with newly diagnosed pulmonary TB. Plasma glucose and TB drug levels were obtained at Week 0, 2, 8 and 24 of TB treatment.RESULTS: A total of 107 patients were included in this analysis. Random plasma glucose ≥200 mg/dL was found in 1/53 (2%) participant at Week 0. The prevalence of FPG ≥ 126 mg/dL decreased from 8/41 (20%) at Week 2 to 3/89 (3%) at Week 24. IFG (100-125 mg/dL) was observed in 23/41 (56%) participants at Week 2, and 39/89 (44%) at Week 24. FPG was inversely correlated with lower area under the curve (AUC_0-24h) for RIF (c = -0.52; 95%CI -0.84 to -0.21; P = 0.001). FPG was not associated with lower INH AUC_0-24h.CONCLUSION: We found a high prevalence of FPG ≥ 126 mg/dL, which decreased significantly during treatment, and a high proportion of IFG at the end of TB treatment. Higher FPG was associated with lower AUC for RIF.

Starting or changing therapy - a prospective study exploring antiretroviral decision-making

BACKGROUND

When to start or change antiretroviral treatment against HIV infection is of major importance. Patients' readiness is considered a major factor influencing such treatment decisions, in particular because no objective, absolute time point when to start antiretroviral therapy exists. We aimed at evaluating patients' readiness to start or change antiretroviral therapy (ART).

PATIENTS AND METHODS

HIV-infected patients starting or changing ART between July 2002 and February 2003, treating physicians and nurses participated in this prospective, observational multicenter study. We assessed shared decision-making including qualitative aspects, expected treatment decisions and treatment status after 3 months.

RESULTS

75 patients were included. Of 34 patients for whom starting ART was considered, 27 (79%) indicated that they were willing to start treatment. After 3 months, 21 of 27 (78%) actually started therapy, six did not. Patients with depression were less likely to be ready for ART (p < 0.05). Of 41 patients for whom changing ART was considered, 35 (85%) indicated that they were willing to change treatment. Of the latter 35 patients, 33 (94%) finally changed ART within 3 months. Physicians and nurses were too optimistic in predicting the start or change of ART. The main reason to start or change ART was the sole recommendation of the physician (52% in those starting, 61% in those changing ART). Patients mainly judged the decision as shared and were very satisfied (71%) with the process. Qualitative findings revealed the importance of a dialectic decisionmaking, described with two categories: "dealing with oneself and others"' and "understanding and being understood."

CONCLUSION

Patients mainly shared the decision made during consultation. Although physicians have an essential role concerning ART, patients, physicians, and nurses all contribute to the decision. Qualitative findings indicate the importance for health-care providers to include patients' expertise and contributions.