The direct emissions related to Global Warming Potential of different types of diagnostic tests at different phases of the COVID pandemic: A climate-focused life-cycle assessment

The healthcare sector is a major consumer of energy and consumables. This is particularly striking in crisis situations, such as COVID 19, which required the massive deployment of testing and vaccination measures, which have a deleterious effect on the environment. In this paper, we assess the Global Warming Potential (GWP) of COVID19 community testing (aimed at mitigating the spread of the virus) using different diagnostic methods and scenarios. A climate-focused Life Cycle Assessment was conducted to assess the Global Warming Potential of self-testing at home and health worker-performed antigen-based rapid diagnostic tests (RDT), as well as laboratory-based PCR tests. The GWP100 indicator and DALYS were used to compare their respective greenhouse gas emissions and expected health impact. Several scenarios were considered, varying the type of test, transport conditions, and pandemic phase. The expected direct emissions GWP of the tests for the same usage scenario is 0.12, 0.23, 0.69 and 0.73 kg CO 2 eq per self-testing RDT, health worker-performed RDT, multiple wells PCR and single PCR respectively. The differences are mainly due to consumables (e.g., protective equipment) and local transport rather than the test itself. The emissions generated by the detection of a true positive is estimated at 1 kg CO 2 eq in the high transmission phase of the pandemic, but at 100 and 2.000 kg CO 2 eq for RDT and PCR respectively in the low transmission phase. When considering the GWP of COVID tests, RDTs are a better option than PCR in all scenarios. For community testing, this is all the more true as there is no clear health benefit either of using PCR rather than RDT. Our results also highlight the disproportionate impact of systematic testing during low transmission phases, due to the very high number of tests needed to detect true contagious cases. It is time to consider not only efficiency but also environmental criteria when designing public health interventions.