Full personal protective equipment (level 1 PPE) is used in various domains and contexts. Prior research has shown positive influences of such equipment on performance, comfort, and contamination levels. The COVID-19 pandemic forced a pervasive requirement of PPE, with little preparation, rushed deployment, inadequate time for training, and massive use by personnel who are inexperienced or not qualified in its effective use.This study aimed to examine the key human factors: physical and ergonomic, perceptual and cognitive, that influence the use of level 1 PPE when attending to suspected or confirmed COVID-19 patients.The research approach consisted of a short survey disseminated to healthcare professionals in two countries, Israel and Portugal, with similar demographics and healthcare systems. The survey included 10 items with a 5-point Likert Scale, regarding the key human factors involved in level 1 PPE, as identified in prior research.A total of 722 respondents from Israel and 301 respondents from Portugal were included in the analysis. All the respondents reported using level 1 PPE with COVID-19 patients in the range of several hours daily to several hours weekly. Cronbach's alpha was .73 for Israel, and .75 for Portugal. Responses showed high levels of difficulty, with medians of 4 for items related to discomfort, hearing and seeing, and doffing. A factor analysis showed a set of strongly related variables consisting of hearing, understanding speech, and understanding the situation. This suggests that degradation in communication was strongly associated with degradation in situational awareness. A subsequent mediation analysis showed a direct effect of PPE discomfort on situational awareness (P<.01); this was also influenced (mediated) by difficulties in communicating, namely in hearing and understanding speech.In 2020, the Covid-19 pandemic is paving the way for updating PPE design. The use of already deployed technology affords ample opportunities to improve, adapt, and overcome caveats. The findings here suggest that the use of level 1 PPE with COVID-19 patients has perceptual and cognitive effects, in addition to physical and ergonomic influences. Efforts should be taken to mitigate harmful effects of such influences, both regarding the performance of medical actions and the risk of contamination to healthcare workers. Such efforts involve the design of PPE; the introduction of technologies to enhance vision, hearing, and communicating during use of PPE; and training staff in using the equipment, and in effective communication and teamwork protocols.