Transmission of SARS-CoV-2 in standardised first few X cases and household transmission investigations: A systematic review and meta-analysis.

We aimed to estimate the household secondary infection attack rate (hSAR) of SARS-CoV-2 in investigations aligned with the WHO Unity Studies Household Transmission Investigations (HHTI) protocol. We conducted a systematic review and meta-analysis according to PRISMA 2020 guidelines. We searched Medline, Embase, Web of Science, Scopus and medRxiv/bioRxiv for "Unity-aligned" First Few X cases (FFX) and HHTIs published 1 December 2019 to 26 July 2021. Standardised early results were shared by WHO Unity Studies collaborators (to 1 October 2021). We used a bespoke tool to assess investigation methodological quality. Values for hSAR and 95% confidence intervals (CIs) were extracted or calculated from crude data. Heterogeneity was assessed by visually inspecting overlap of CIs on forest plots and quantified in meta-analyses. Of 9988 records retrieved, 80 articles (64 from databases; 16 provided by Unity Studies collaborators) were retained in the systematic review; 62 were included in the primary meta-analysis. hSAR point estimates ranged from 2% to 90% (95% prediction interval: 3%-71%; I 2 = 99.7%); I 2 values remained >99% in subgroup analyses, indicating high, unexplained heterogeneity and leading to a decision not to report pooled hSAR estimates. FFX and HHTI remain critical epidemiological tools for early and ongoing characterisation of novel infectious pathogens. The large, unexplained variance in hSAR estimates emphasises the need to further support standardisation in planning, conduct and analysis, and for clear and comprehensive reporting of FFX and HHTIs in time and place, to guide evidence-based pandemic preparedness and response efforts for SARS-CoV-2, influenza and future novel respiratory viruses.

Long-term outcomes of Guillain-Barré syndrome possibly associated with Zika virus infection.

BACKGROUND: This prospective cohort investigation analyzed the long-term functional and neurologic outcomes of patients with Zika virus-associated Guillain-Barré syndrome (GBS) in Barranquilla, Colombia. METHODS: Thirty-four Zika virus-associated GBS cases were assessed a median of 17 months following acute GBS illness. We assessed demographics, results of Overall Disability Sum Scores (ODSS), Hughes Disability Score (HDS), Zung Depression Scale (ZDS), and Health Related Quality of Life (HRQL) questionnaires; and compared outcomes indices with a normative sample of neighborhood-selected control subjects in Barranquilla without GBS. RESULTS: Median age at time of acute neurologic onset was 49 years (range, 10-80); 17 (50%) were male. No deaths occurred. At long-term follow-up, 25 (73%) patients had a HDS 0-1, indicating complete / near complete recovery. Among the group, HDS (mean 1.4, range 0-4), ODSS (mean 1.9, range 0-9) and ZDS score (mean 34.4, range 20-56) indicated mild / moderate ongoing disability. Adjusting for age and sex, Zika virus-associated GBS cases were similar to a population comparison group (n = 368) in Barranquilla without GBS in terms of prevalence of physical or mental health complaints, though GBS patients were more likely to have an ODSS of ≥ 1 (OR 8.8, 95% CI 3.2-24.5) and to suffer from moderate / moderate-severe depression (OR 3.89, 95% CI 1.23-11.17) than the comparison group. CONCLUSIONS: Long-term outcomes of Zika virus-associated GBS are consistent with those associated with other antecedent antigenic stimuli in terms of mortality and ongoing long-term morbidity, as published in the literature. Persons with Zika virus-associated GBS more frequently reported disability and depression after approximately one year compared with those without GBS.