Update Alert 2: Ventilation Techniques and Risk for Transmission of Coronavirus Disease, Including COVID-19.

We have updated the protocol of our living systematic review (PROSPERO registration: CRD42020178187). This most recent search update, which was done on 11 July 2020, identified 2756 citations. Of these, we included 3 observational cohort studies of patients with coronavirus disease 2019 (COVID-19) in the updated quantitative synthesis (1–3). One of the new studies compared bilevel positive airway pressure (BiPAP) with continuous positive airway pressure (CPAP) (1), 1 compared high-flow oxygen by nasal cannula (HFNC) with invasive mechanical ventilation (IMV) (2), and the last compared noninvasive ventilation (NIV) with IMV (3) (Supplement Table 1).