Assessing Sociodemographic Factors Associated with Household Hardships during the COVID-19 Pandemic in Manhica, Mozambique using Data Collected between April 2021 and February 2022 (preprint)

BackgroundCOVID-19 resulted in vast disruption to life in the 21st century. To quell the disease spread, national governments implemented several containment measures like state of emergency, curfews, and lockdowns that likely created hardships for households. To improve knowledge of the negative consequences of these lockdowns, we examine the extent to which the pandemic period was associated with hardships at the household level and assess factors associated with household vulnerability to these hardships. MethodsWe conducted a cross-sectional survey between April 2021 and February 2022 among households residing in the district of Manhica through a survey questionnaire fielded in the Health and Demographic Surveillance System (HDSS) operating in Manhica, Mozambique. Logistic regression was used to analyze associations between the head of household and household characteristics with specific household hardships (business closure, food price increase, household member detained, input inflation, job loss). ResultsHouseholds headed by individuals with lower education and employed in non-agricultural occupations as well as households that were larger in size or poorer in asset ownership compared to other households were generally at greater risk of experiencing a larger variety of hardships. Conversely, households that owned "distance demolishing technologies" such as motorcycles were less likely to experience these hardships, presumably as they were able to transcend local conditions. ConclusionsThese results identify at-risk groups according to a social determinants of vulnerability framework and will help inform future policies and practices that aim to mitigate the negative consequences of COVID-19 as well as future disease outbreaks.

Knowledge of COVID-19 Symptoms, Transmission, and Prevention: Evidence from Health and Demographic Surveillance in Southern Mozambique (preprint)

Background: Over 230,000 COVID-19 cases and over 2,200 deaths have been reported in Mozambique though March 2023. Understanding community members' knowledge and perception of SARS-CoV-2 transmission and prevention is essential for directing public health interventions to reduce disease spread and improve vaccination coverage. Here, we aimed to describe knowledge of COVID-19 transmission, prevention, and symptoms among community residents in Mozambique. Methods: We conducted a cross-sectional survey among 33,087 of 40,636 households (81.4%) in a Health and Demographic Surveillance System in Manhica, Mozambique, at the tail end of the Delta variant wave in September 2021 to the peak of Omicron cases in January 2022. Principal components analysis was used to create scores representing knowledge of COVID-19 symptoms, transmission, and prevention. Multiple imputation and quasi-Poisson regression were used to examine associations between demographic characteristics and sources of COVID-19 information, and knowledge of COVID-19 symptoms, transmission, and prevention. We examined whether sources of COVID-19 information mediated the relationship between educational attainment and knowledge of symptoms, transmission, and prevention. Results: Across this rural community, 98.2%, 97.0%, and 85.1% of household respondents reported knowing how COVID-19 could be prevented, that SARS-CoV-2 can cause disease, and how SARS-CoV-2 is transmitted, respectively. Most recognized symptoms were cough (51.2%), headaches (44.9%), and fever (44.5%). Most cited transmission mechanisms were droplets (50.5%) or aerosol (<5 micrometer diameter) (46.9%) from an infected person. Most cited prevention measures were handwashing (91.9%) and mask-wearing (91.8%). Characteristics associated with greater knowledge of symptoms, transmission, and prevention included having at least primary education, older age, employment, higher wealth, and Christian religion. Respondents who had had COVID-19 symptoms were also more likely to have knowledge of symptoms, transmission, and prevention. Gathering information from TV, WhatsApp, radio, and hospital mediated the relationship between educational attainment and knowledge scores. Conclusions: Community public health measures to reduce infectious disease transmission are contingent upon perceptions of risk and knowledge. These findings support the need for outreach and for community-engaged messaging to promote prevention measures, particularly among people with low education.

Perceptions and compliance with COVID-19 preventive measures in Southern and Central regions of Mozambique: a quantitative in-person household survey in the districts of Manhica and Quelimane (preprint)

Background The COVID-19 pandemic has led countries into urgent implementation of stringent preventive measures at the population level. However, implementing these measures in low-income countries like Mozambique was incredibly difficult, coupled with lack of scientific evidence on the community understanding and compliance with these measures. This study assessed the perceptions and implementation of COVID-19 preventive measures recommended by Mozambican authorities in Manhica and Quelimane districts, taking confinement, social distancing, frequent handwashing, mask wearing, and quarantine as the key practices to evaluate. Methods A quantitative survey interviewing households heads in-person was conducted in October 2020 and February 2021; collecting data on perceptions of COVID-19, symptoms, means of transmission/prevention; including self-evaluation of compliance with the key measures, existence of handwashing facilities, and the ratio of face-masks per person. The analysis presents descriptive statistics on perceptions and compliance with anti-COVID-19 measures at individual and household levels, comparing by district and other variables. T-test was performed to assess the differences on proportions between the districts or categories of respondents in the same district. Results The study interviewed 770 individuals of which 62.3% were heads of households, 18.6% their spouses, and 11.0% sons/daughters. Most participants (98.7%) had heard of COVID-19 disease. The most difficult measure to comply with was staying at home (35.8% of respondents said they could not comply with it at all); followed by avoiding touching the month/nose/eyes (28.7%), and social distancing at home (27.3%). Mask wearing in public places was the measure that more respondents (48.8%) thought they complied 100% with it, followed by avoiding unnecessary traveling (40.0%), avoiding crowed places (34.0%), and social distancing outside home (29.0%). Only 30.4% of households had handwashing devices or disinfectant (36.7% in Manhica and 24.1% in Quelimane); and of those with devices, only 41.0% had water in the device, 37.6% had soap, and 22.6% had other disinfectant. The ratio of masks per person was only 1, which suggests that people may have used the same mask for longer periods than recommended. Conclusions Community members in Manhica and Quelimane were aware of COVID-19 but they lacked understanding for implementing the preventive measures. This, together with socio-economic constraints, led to lower levels of compliance with the key measures. Understanding and addressing the factors affecting proper implementation of these measures is crucial for informing decision-makers about ways to improve community knowledge and practices to prevent infectious diseases with epidemic potential.

Convalescent plasma for outpatients with early COVID-19 (preprint)

Background: Convalescent plasma (CP) for hospitalized patients with COVID-19 has not demonstrated clear benefits. However, data on outpatients with early symptoms are scarce. We aimed to assess whether treatment with CP administered during the first 7 days of symptoms reduced the disease progression or risk of hospitalization of outpatients. Methods: Two double-blind randomized trials (NCT04621123, NCT04589949) were merged with data pooling starting when <20% of their predefined sample size had been recruited. A Bayesian adaptive individual patient data meta-analysis was implemented. Analyses were done with Bayesian proportional odds and logistic models, where odds ratios (OR)<1.0 indicate a favorable outcome for CP. Fourteen study sites across the Netherlands and Catalonia in Spain participated in the trial. The two studies included outpatients aged [≥]50 years and diagnosed with COVID-19 and symptomatic for [≤]7days. The intervention consisted of one unit (200-300mL) of CP with a predefined minimum level of antibodies. The two primary endpoints were (a) a 5-point disease severity scale (fully recovered by day 7 or not, hospital or ICU admission and death) and (b) a composite of hospitalization or death. Results: Of 797 patients included, 390 received CP and 392 placebo. At baseline, they had a median age of 58 years, 1 comorbidity, symptoms for 5 days and 93% tested negative for SARS-CoV-2 S-protein IgG antibodies. Seventy-four patients were hospitalized, 6 required mechanical ventilation and 3 died. The OR of CP for an improved disease severity scale was 0.936 (credible interval (CI) 0.667-1.311). The OR for hospitalization or death was 0.919 (CI 0.592-1.416). The effect of CP on hospital admission or death was largest in patients with [≤]5 days of symptoms (OR 0.658, 95% CI 0.394-1.085). CP did not decrease the time to full symptom resolution (p=0.62). Conclusion: Treatment with CP of outpatients in the first 7 days of symptoms did not improve the outcome of COVID-19. The possible beneficial effect in patients with [≤]5 days of symptoms requires further study. Registration: NCT04621123 and NCT04589949 on https://www.clinicaltrials.gov

Antibody Conversion rates to SARS-CoV-2 in Saliva from Children Attending Summer Schools in Barcelona, Spain (preprint)

Surveillance tools to estimate infection rates in young populations are essential to guide recommendations for school reopening and management during viral epidemics. Ideally, field-deployable non-invasive, sensitive techniques are required to detect low viral load exposures among asymptomatic children. We determined SARS-CoV-2 antibody conversion by high-throughput Luminex assays in saliva samples collected weekly in 1,509 children and 396 adults in 22 Summer schools and 2 pre-schools in 27 venues in Barcelona, Spain, from June 29th to July 31st 2020, between the first and second COVID-19 pandemic waves. Saliva antibody conversion defined as [≥]4-fold increase in IgM, IgA and/or IgG levels to SARS-CoV-2 antigens between two visits over a 5-week period was 3.22% (49/1518), or 2.36% if accounting for potentially cross-reactive antibodies, six times higher than the cumulative infection rate (0.53%) by weekly saliva RT-PCR screening. IgG conversion was higher in adults (2.94%, 11/374) than children (1.31%, 15/1144) (p=0.035), IgG and IgA levels moderately increased with age, and antibodies were higher in females. Most antibody converters increased both IgG and IgA antibodies but some augmented either IgG or IgA, with a faster decay over time for IgA than IgG. Nucleocapsid rather than spike was the main antigen target. Anti-spike antibodies were significantly higher in individuals not reporting symptoms than symptomatic individuals, suggesting a protective role against COVID-19. To conclude, saliva antibody profiling including three isotypes and multiplexing antigens is a useful and more user-friendly tool for screening pediatric populations to determine SARS-CoV-2 exposure and guide public health policies during pandemics.

Multiplex Antibody Analysis of IgM, IgA and IgG to SARS-CoV-2 in Saliva and Serum from Infected Children and their Close Contacts (preprint)

COVID-19 affects children to a lesser extent than adults but they can still get infected and transmit SARS-CoV-2 to their contacts. Field deployable non-invasive sensitive diagnostic techniques are needed to evaluate the infectivity dynamics of the coronavirus in pediatric populations and guide public health interventions. We evaluated the utility of high-throughput Luminex-based assays applied to saliva samples to quantify IgM, IgA and IgG antibodies against five SARS-CoV-2 spike (S) and nucleocapsid (N) antigens in the context of a contacts and infectivity longitudinal study. We compared the antibody levels obtained in saliva versus serum/plasma samples from a group of children and adults tested weekly by RT-PCR over 35 days and diagnosed as positive (n=58), and a group of children and adults who consistently tested negative over the follow up period (n=61), in the Summer of 2020 in Barcelona, Spain. Antibody levels in saliva samples from individuals with confirmed RT-PCR diagnosis of SARS-CoV-2 infection were significantly higher than in negative individuals and correlated with those measured in sera/plasmas. Higher levels of anti-S IgG were found in asymptomatic individuals that could indicate protection against disease in infected individuals. Higher anti-S IgG and IgM levels in serum/plasma and saliva, respectively, in infected children compared to infected adults could also be related to stronger clinical immunity in them. Among infected children, males had higher levels of saliva IgG to N and RBD than females. Despite overall correlation, individual clustering analysis suggested that responses that may not be detected in blood could be patent in saliva, and vice versa, and therefore that both measurements are complementary. In addition to serum/plasma, measurement of SARS-CoV-2-specific saliva antibodies should be considered as a complementary non-invasive assay to better estimate the percentage of individuals who have experienced coronavirus infection. Saliva antibody detection could allow determining COVID-19 prevalence in pediatric populations, alternative to bleeding or nasal swab, and serological diagnosis following vaccination.

Performance characteristics of five antigen-detecting rapid diagnostic test (Ag-RDT) for SARS-CoV-2 asymptomatic infection: a head-to-head benchmark comparison (preprint)

Background Mass testing for early identification and isolation of infectious COVID-19 individuals, irrespective of concurrent symptoms, is an efficacious strategy to reduce disease transmission. Antigen-detecting rapid diagnostic tests (Ag-RDT) appear as a potentially suitable tool for mass testing on account of their ease-of-use, fast turnaround time, and low cost. However, benchmark comparisons are scarce, particularly in the context of unexposed asymptomatic individuals. Methods We used nasopharyngeal specimens from unexposed asymptomatic individuals to assess five Ag-RDTs: PanBio ™ COVID-19 Ag Rapid test (Abbott), CLINITEST® Rapid COVID-19 Antigen Test (Siemens), SARS-CoV-2 Rapid Antigen Test (Roche Diagnostics), SARS-CoV-2 Antigen Rapid Test Kit (Lepu Medical), and COVID-19 Coronavirus Rapid Antigen Test Cassette (Surescreen). Samples were collected between December 2020-January 2021 during the third wave of the epidemic in Spain. Findings The analysis included 101 specimens with confirmed positive PCR results and 185 with negative PCR. For the overall sample, the performance parameters of Ag-RDTs were as follows: Abbott assay, sensitivity 38·6% (95% CI 29·1–48·8) and specificity 99·5% (97–100%); Siemens, sensitivity 51·5% (41·3–61·6) and specificity 98·4% (95·3–99·6); Roche, sensitivity 43·6% (33·7–53·8) and specificity 96·2% (92·4–98·5); Lepu, sensitivity 45·5% (35·6–55·8) and specificity 89·2% (83·8–93·3%); Surescreen, sensitivity 28·8% (20·2–38·6) and specificity 97·8% (94·5–99·4%). For specimens with cycle threshold (Ct) <30 in RT-qPCR, all Ag-RDT achieved a sensitivity of at least 70%, with Siemens, Roche, and Lepu assays showing sensitivities higher than 80%. In models according to population prevalence, all Ag-RDTs will have a NPV >99% and a PPV<50% at 1% prevalence. Interpretation Two commercial, widely available assays can be used for SARS-CoV-2 antigen testing to achieve sensitivity in specimens with a Ct<30 and specificity of at least 80% and 96%, respectively. Estimated negative and positive predictive values suggests the suitability of Ag-RDTs for mass screenings of SARS-CoV-2 infection in the general population. Funding Blueberry diagnostics, Fundació Institut d’Investigació en Ciències de la Salut Germans Trias i Pujol, and #YoMeCorono.org crowdfunding campaign. Research in context Evidence before this study In December 2020, we searched on PubMed for articles containing the terms “antigen”, “test” (or Ag-RDT), and “SARS-CoV-2” or “COVID-19” either in the title or the abstract. Our search yielded 79 entries corresponding to articles written in English. Of them, 33 were articles presenting the diagnostic performance of qualitative lateral-flow antigen-detecting rapid diagnostic tests (Ag-RDT). Four of these articles reported the results of head-to-head comparisons of various Ag-RDTs; in all cases, the number of tests was lower than the recommended for retrospective assessments of diagnostic performance (i.e., minimum of 100 PCR positive and 100 PCR negative). Furthermore, all head-to-head comparisons found in the literature included specimens obtained among individuals with varying disease status (none of which asymptomatic), thus limiting the adequacy of the estimates for an asymptomatic screening strategy. Added value of this study We compared for the first time head-to-head five Ag-RDT using a powered set of fresh respiratory specimens PCR-confirmed positive or negative, collected from unexposed asymptomatic individuals during screening campaigns for early detection of SARS-CoV-2 infection. The sample size was large enough to draw robust conclusions. Our analysis identified four Ag-RDTs (i.e., assays marketed by Abbott, Siemens, Roche, and Surescreen) with specificity higher than 96%. Despite the low sensitivity for the overall sample (range 29% to 51%), the corresponding values for the subset of samples with Ct <30 were higher than 80% for Siemens, Roche, and Lepu assays. The estimated NPV for a screening performed in an area with 1% prevalence would be >99% for all tests, while the PPV would be <50%. Implications of all the available evidence Current data on the diagnostic performance of Ag-RDTs is heterogeneous and precludes benchmark assessments. Furthermore, the screening of asymptomatic populations is currently not considered among the intended uses of Ag-RDT, mostly because of lack of evidence on test performance in samples from unexposed asymptomatic individuals. Our findings add to the current evidence in two ways: first, we provide benchmarking data on Ag-RDTs, assessed head-to-head in a single set of respiratory specimens; second, we provide data on the diagnostic performance of Ag-RDTs in unexposed asymptomatic individuals. Our findings support the idea that Ag-RDTs can be used for mass screening in low prevalence settings and accurately rule out a highly infectious case in such setting.

Validation and implementation of a direct RT-qPCR method for rapid screening of SARS-CoV-2 infection by using non-invasive saliva samples (preprint)

Objective To validate and implement an optimized screening method for detection of SARS-CoV-2 RNA combining use of self-collected raw saliva samples, single-step heat-treated virus inactivation and RNA extraction, and direct RT-qPCR. Design Study conducted in three successive phases including: i) method analytical validation against standard RT-qPCR in saliva samples; ii), method diagnostic validation against standard RT-qPCR in nasopharyngeal samples; and iii), method implementation through pilot screening in a reference hospital. Setting Sant Joan de Deu University Hospital (Barcelona, Spain). Participants Phase 2, a prospective cohort of asymptomatic teenagers and young adult players and staff in a youth sports academy followed up during 9 to 12 weeks; Phase 3, asymptomatic health workers, students, aid volunteers, and other staff of the setting. Main outcome measures Method diagnostic sensitivity and specificity. Method performance in a pilot screening. Results Diagnostic validation included 173 participants. At week 0, all saliva and nasopharyngeal samples were negative. In the following weeks, standard RT-qPCR yielded 23 positive results in nasopharyngeal samples. Paired saliva specimens yielded 22 positive and one inconclusive result. Method diagnostic sensitivity and specificity values were 95.7% (95% CI, 79.0-99.2%) and 100.0% (95% CI, 98.6-100.0 %), respectively. A total of 2,709 participants engaged in the pilot screening, with a high rate of participation (83.4% among health workers). Only 17 (0.6%) of saliva samples self-collected by participants in an unsupervised manner were invalid. Saliva was positive in 24 (0.9%) out of 2,692 valid specimens and inconclusive in 27 (1.0%). All 24 saliva-positive and 4 saliva-inconclusive participants were positive by standard RT-PCR in nasopharyngeal samples. Use of a high throughput system allowed fast screening workflow (up to 384 samples in <2 hours). Conclusion Direct RT-qPCT on self-collected raw saliva is a simple, rapid, and accurate method with potential to be scaled up for enhanced SARS-CoV-2 community-wide screening.

Validation and Implementation of a Direct RT-qPCR Method for Rapid Screening of SARS-CoV-2 Infection by Using Non-Invasive Saliva Samples (preprint)

Background: There is an urgent need to curb COVID-19 pandemic through early identification of asymptomatic but infectious cases. We aimed to validate and implement an optimized screening method for detection of SARS-CoV-2 RNA combining use of self-collected raw saliva samples, single-step heat-treated virus inactivation and RNA extraction, and direct RT-qPCR.Methods: The study was conducted in Sant Joan de Déu University Hospital (Barcelona, Spain), including: i) method analytical validation against standard RT-qPCR in saliva samples; ii) method diagnostic validation against standard RT-qPCR in nasopharyngeal samples using a prospective cohort of asymptomatic teenagers and young adult players and staff in a youth sports academy; and iii) method implementation through pilot screening of asymptomatic health workers, students, and aid volunteers in the study site.Findings: The direct method had comparable performance to standard RT-qPCR in saliva and high intra- and inter-assay precision. Diagnostic validation included saliva and nasopharyngeal samples serially obtained from 173 participants during 9-12 weeks. At week 0, all saliva and nasopharyngeal samples were negative. In the following weeks, standard RT-qPCR yielded 23 positive results in nasopharyngeal samples. Paired saliva specimens yielded 22 (95·7%) positive and one inconclusive result. A total of 2,709 participants engaged in the pilot screening, with a high rate of participation (83·4% among health workers). Only 17 (0·6%) of saliva samples self-collected by participants were invalid. Saliva was positive in 24 (0·9%) out of 2,692 valid specimens and inconclusive in 27 (1·0%). All 24 saliva-positive and 4 saliva-inconclusive participants were positive by standard RT-PCR in nasopharyngeal samples. Use of a high throughput system allowed fast screening workflow (up to 384 samples in <2 hours).Interpretation: Direct RT-qPCT on self-collected raw saliva is a simple, rapid, and accurate method with potential to be scaled up for enhanced SARS-CoV-2 community-wide screening.Funding:This work was supported by the Kids Corona Project promoted by SJDH, which received donations from Stavros Niarchos Foundation and Banco Santander.Declaration of Interests: CMA reports past grants to her organization from BioMèrieux, Roche Diagnostics, Qiagen, BioFire Diagnostics, Alere, and Genomica, outside the submitted work and personal fees from BioMèrieux, Roche Diagnostics, and Qiagen for presentations in satellite symposiums outside the submitted work. PB reports personal fees from Roche Diagnostics for a presentation in a satellite symposium outside the submitted work. The rest of authors declare no conflicts of interest.Ethics Approval Statement: The study was approved by the Ethics Commitee of SJDH prior to the beginning of activities (ref. PIC-240-20). Use of samples collected from participants in the “Kids Corona Study of SARS-CoV-2 transmission at Football Club Barcelona Academy “La Masia” for the present and future studies was covered in the informed consent process and approval of that study (ref. PIC-200-20).

Chloroquine diphosphate in two different dosages as adjunctive therapy of hospitalized patients with severe respiratory syndrome in the context of coronavirus (SARS-CoV-2) infection: Preliminary safety results of a randomized, double-blinded, phase IIb clinical trial (CloroCovid-19 Study) (preprint)

Background There is no specific antiviral therapy recommended for the disease caused by SARS-CoV-2 (COVID-19). Recent publications have drawn attention to the possible benefit of chloroquine (CQ). Our study aimed to comprehensively evaluate the safety and efficacy of two different CQ dosages in patients with established severe COVID-19. Methods We performed a parallel, double-blinded, randomized, phase IIb clinical trial, aiming to assess safety and efficacy of two different CQ dosages as adjunctive therapy of hospitalized patients with SARS in Manaus, Brazilian Amazon. Eligible participants were allocated to receive orally or via nasogastric tube high dose CQ (600mg CQ twice daily for 10 days or total dose 12g); or low dose CQ (450mg for 5 days, twice daily only on the first day, or total dose 2.7g). In addition, all patients received ceftriaxone and azithromycin. This study was registered with ClinicalTrials.gov, number NCT04323527. Findings Out of a pre-defined 440 patients sample size, 81 patients were enrolled. The high dose CQ arm presented more QTc>500ms (25%), and a trend toward higher lethality (17%) than the lower dosage. Fatality rate was 13.5% (95%CI=6.9-23.0%), overlapping with the CI of historical data from similar patients not using CQ (95%CI=14.5-19.2%). In 14 patients with paired samples, respiratory secretion at day 4 was negative in only one patient. Interpretation Preliminary findings suggest that the higher CQ dosage (10-day regimen) should not be recommended for COVID-19 treatment because of its potential safety hazards. Such results forced us to prematurely halt patient recruitment to this arm. Given the enormous global push for the use of CQ for COVID-19, results such as the ones found in this trial can provide robust evidence for updated COVID-19 patient management recommendations.