Household transmission of SARS-CoV-2 in a rural area in South Africa

BACKGROUND

Patterns of SARS-CoV-2 spread have varied by geolocation, with differences in seroprevalence between urban and rural areas, and between waves. Household spread of SARS-CoV-2 is a known source of new COVID-19 infections, with rural areas in sub-Saharan Africa being more prone than urban areas to COVID-19 transmission because of limited access to water in some areas, delayed health- seeking behaviour and poor access to care.

OBJECTIVES

To explore SARS-CoV-2 infection incidence and transmission in rural households in South Africa (SA).

METHODS

We conducted a prospective household cluster investigation between 13 April and 21 July 2021 in the Matjhabeng subdistrict, a rural area in Free State Province, SA. Adults with SARS-CoV-2 confirmed by polymerase chain reaction (PCR) tests (index cases, ICs) and their household contacts (HCs) were enrolled. Household visits conducted at enrolment and on days 7, 14 and 28 included interviewer- administered questionnaires and respiratory and blood sample collection for SARS-CoV-2 PCR and SARS-CoV-2 immunoglobulin G serological testing, respectively. Co-primary cases were HCs with a positive SARS-CoV-2 PCR test at enrolment. The incidence rate (IR), using the Poisson distribution, was HCs with a new positive PCR and/or serological test per 1 000 person-days. Associations between outcomes and HC characteristics were adjusted for intra-cluster correlation using robust standard errors. The secondary infection rate (SIR) was the proportion of new COVID-19 infections among susceptible HCs.

RESULTS

Among 23 ICs and 83 HCs enrolled, 10 SARS-CoV-2 incident cases were identified, giving an IR of 5.8 per 1 000 person-days (95% confidence interval (CI) 3.14 - 11.95). Households with a co-primary case had higher IRs than households without a co-primary case (crude IR 14.16 v. 1.75, respectively; p=0.054). HIV infection, obesity and the presence of chronic conditions did not materially alter the crude IR. The SIR was 15.9% (95% CI 7.90 - 29.32). Households with a lower household density (fewer household members per bedroom) had a higher IR (IR 9.58; 95% CI 4.67 - 21.71) than households with a higher density (IR 3.06; 95% CI 1.00 - 12.35).

CONCLUSION

We found a high SARS-CoV-2 infection rate among HCs in a rural setting, with 48% of households having a co-primary case at the time of enrolment. Households with co-primary cases were associated with a higher seroprevalence and incidence of SARS-CoV-2. Sociodemographic and health characteristics were not associated with SARS-CoV-2 transmission in this study, and we did not identify any transmission risks inherent to a rural setting.

Host biomarkers for early identification of severe imported Plasmodium falciparum malaria

BACKGROUND

Severe imported P. falciparum malaria is a source of morbi-mortality in non-endemic regions. WHO criteria don't accurately classify patients at risk of complications. There is a need to evaluate new tools such as biomarkers to better identify patients with severe imported malaria.

METHODS

A case-control study was conducted in Barcelona, from January 2011-January 2021. Adult patients with microbiologically confirmed P. falciparum malaria were classified according to WHO criteria. Patients with imported non-malarial fevers were included as controls. In each group, angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), soluble triggering receptor expressed on myeloid cells (sTREM-1), C-reactive protein (CRP) and platelets were measured and their concentrations were compared between groups. New groups were made with a modified WHO severity classification and biomarkers' performance was evaluated using multiple imputation models.

RESULTS

131 participants were included: 52 severe malaria, 30 uncomplicated malaria and 49 non-malarial fever cases. All biomarkers except sTREM-1 showed significant differences between groups. Using the modified WHO severity classification, Ang-2 and CRP presented the best AUROC; 0.79 (95%CI 0.64-0.94) and 0.80(95%CI 0.67-0.93). A model combining CRP and Ang-2 showed the best AUROC, of 0.84(95%CI 0.68-0.99), with the highest sensitivity and specificity: 84.6%(95%CI 58.9-98.1) and 77.4% (95%CI 65.9-87.7), respectively.

CONCLUSIONS

The combination of Ang-2 and CRP may be a reliable tool for the early identification of severe imported malaria. The use of a rapid prognostic test including the mentioned biomarkers could optimize imported malaria management, with the potential to decrease the rate of complications and hospitalizations in patients with imported malaria.

Telemedicine for international travelers through a Smartphone-based monitoring platform (Trip Doctor®)

BACKGROUND

Overall, more than 50% of international travelers develop symptoms while traveling and 55% of them seek medical assistance during the trip. We conducted a study to evaluate the usefulness of a Smartphone app called TRIP Doctor® to provide telemedicine to international travelers.

METHODS

Participants over 18 years old attending our travel clinic at Hospital Clinic in Barcelona were invited to participate during 2017-2019. After downloading the app, the health status of the traveler was monitored on a daily basis, providing specific medical advice and offering remote contact with specialized physicians through an integrated chat, if needed.

RESULTS

From 449 users, 59 (13%) contacted for medical assistance through the app during the trip. Main reasons for telemedicine were diarrhea (25.7%), skin conditions (19.7%) and fever (12.1%). Among patients who contacted, 90% of the travelers did not require to be referred to a local doctor. Symptomatic treatment was the main treatment prescribed (38%). In a 14.7% of the cases a follow-up was not required, a 63.2% recovered and 22.1% were loss of follow-up. After a multivariate analysis, duration of trip >14 days was found to be the only factor associated with the use of telemedicine (OR 2.2, CI 95% 1.1-4.5, p = 0.03).

CONCLUSION

In conclusion, travelers using telemedicine travelled for longer periods of time and mostly contacted for mild symptoms which could be solved successfully by remote assistance with our specialized doctors.

Incidence of human granulocytic anaplasmosis in returning travellers with fever

BACKGROUND

Although tick-borne pathogens have been reported as an important cause of imported fever, the incidence of Anaplasma phagocytophilum, the causative agent of human granulocytic anaplasmosis (HGA), in travellers is unknown.

METHODS

We conducted a prospective cohort study to investigate the aetiologies of fever in returning travellers (November 2017-July 2019). Polymerase chain reaction for msp2 gene amplification and indirect immunofluorescence assay for A. phagocitophilum were performed in all returning travellers with undifferentiated non-malarial fever.

RESULTS

Among 141 travellers included, 8 patients were diagnosed with probable or confirmed HGA. The overall incidence rate of HGA was 19.9 cases/1000 person-week of travel. The main destination of travel was Asia, accounting for 62.5% patients with HGA. Co-infections were found in 37.5% of patients with HGA.

CONCLUSIONS

Diagnosis of HGA and empirical treatment with doxycycline should be considered in travellers with fever.

Tocilizumab reduces the risk of ICU admission and mortality in patients with SARS-CoV-2 infection

Objectives

In some patients the immune response triggered by SARS-CoV-2 is unbalanced, presenting an acute respiratory distress syndrome which in many cases requires intensive care unit (ICU) admission. The limitation of ICU beds has been one of the major burdens in the management around the world; therefore, clinical strategies to avoid ICU admission are needed. We aimed to describe the influence of tocilizumab on the need of transfer to ICU or death in non-critically ill patients.

Material and methods

A retrospective study of 171 patients with SARS-CoV-2 infection that did not qualify as requiring transfer to ICU during the first 24h after admission to a conventional ward, were included. The criteria to receive tocilizumab was radiological impairment, oxygen demand or an increasing of inflammatory parameters, however, the ultimate decision was left to the attending physician judgement. The primary outcome was the need of ICU admission or death whichever came first.

Results

A total of 77 patients received tocilizumab and 94 did not. The tocilizumab group had less ICU admissions (10.3% vs. 27.6%, P=0.005) and need of invasive ventilation (0 vs 13.8%, P=0.001). In the multivariable analysis, tocilizumab remained as a protective variable (OR: 0.03, CI 95%: 0.007-0.1, P=0.0001) of ICU admission or death.

Conclusions

Tocilizumab in early stages of the inflammatory flare could reduce an important number of ICU admissions and mechanical ventilation. The mortality rate of 10.3% among patients receiving tocilizumab appears to be lower than other reports. This is a non-randomized study and the results should be interpreted with caution.