Communicable diseases in complex emergencies: impact and challenges.

Communicable diseases, alone or in combination with malnutrition, account for most deaths in complex emergencies. Factors promoting disease transmission interact synergistically leading to high incidence rates of diarrhoea, respiratory infection, malaria, and measles. This excess morbidity and mortality is avoidable as effective interventions are available. Adequate shelter, water, food, and sanitation linked to effective case management, immunisation, health education, and disease surveillance are crucial. However, delivery mechanisms are often compromised by loss of health staff, damage to infrastructure, insecurity, and poor co-ordination. Although progress has been made in the control of specific communicable diseases in camp settings, complex emergencies affecting large geographical areas or entire countries pose a greater challenge. Available interventions need to be implemented more systematically in complex emergencies with higher levels of coordination between governments, UN agencies, and non-governmental organisations. In addition, further research is needed to adapt and simplify interventions, and to explore novel diagnostics, vaccines, and therapies

Airborne transmission of SARS-CoV-2 via aerosols

 A key consideration in the Covid-19 pandemic is the dominant modes of transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. The objective of this review was to synthesise the evidence for the potential airborne transmission of SARS-CoV-2 via aerosols. Systematic literature searches were conducted in PubMed, Embase, Europe PMC and National Health Service UK evidence up to 27 July 2020. A protocol was published and Cochrane guidance for rapid review methodology was adhered to throughout. Twenty-eight studies were identified. Seven out of eight epidemiological studies suggest aerosol transmission may occur, with enclosed environments and poor ventilation noted as possible contextual factors. Ten of the 16 air sampling studies detected SARS-CoV-2 ribonucleic acid; however, only three of these studies attempted to culture the virus with one being successful in a limited number of samples. Two of four virological studies using artificially generated aerosols indicated that SARS-CoV-2 is viable in aerosols. The results of this review indicate there is inconclusive evidence regarding the viability and infectivity of SARS-CoV-2 in aerosols. Epidemiological studies suggest possible transmission, with contextual factors noted. Viral particles have been detected in air sampling studies with some evidence of clinical infectivity, and virological studies indicate these particles may represent live virus, adding further plausibility. However, there is uncertainty as to the nature and impact of aerosol transmission of SARS-CoV-2, and its relative contribution to the Covid-19 pandemic compared with other modes of transmission. </p