Feurer, DeniseDeniseFeurerRiffe, TimTimRiffeKniffka, Maxi StellaMaxi StellaKniffkaAcosta, EnriqueEnriqueAcostaArmstrong, BenBenArmstrongMistry, MalcolmMalcolmMistryLowe, RachelRachelLoweRoyé, DominicDominicRoyéHashizume, MasahiroMasahiroHashizumeMadaniyazi, LinaLinaMadaniyaziNg, Chris Fook ShengChris Fook ShengNgTobias, AurelioAurelioTobiasÍñiguez, CarmenCarmenÍñiguezVicedo-Cabrera, Ana MariaAna MariaVicedo-CabreraRagettli, Martina SMartina SRagettliLavigne, EricEricLavigneCorrea, Patricia MatusPatricia MatusCorreaOrtega, Nicolás ValdésNicolás ValdésOrtegaKyselý, JanJanKyselýUrban, AlešAlešUrbanOrru, HansHansOrruIndermitte, EneEneIndermitteMaasikmets, MarekMarekMaasikmetsDallavalle, MarcoMarcoDallavalleSchneider, AlexandraAlexandraSchneiderHonda, YasushiYasushiHondaAlahmad, BarrakBarrakAlahmadZanobetti, AntonellaAntonellaZanobettiSchwartz, JoelJoelSchwartzCarrasco, GabrielGabrielCarrascoHolobâca, Iulian HoriaIulian HoriaHolobâcaKim, HoHoKimLee, WhanheeWhanheeLeeBell, Michelle LMichelle LBellScovronick, NoahNoahScovronickAcquaotta, FiorellaFiorellaAcquaottaCoélho, Micheline de Sousa Zanotti StagliorioMicheline de Sousa Zanotti StagliorioCoélhoDiaz, Magali HurtadoMagali HurtadoDiazArellano, Eunice Elizabeth FélixEunice Elizabeth FélixArellanoMichelozzi, PaolaPaolaMichelozziStafoggia, MassimoMassimoStafoggiade'Donato, FrancescaFrancescade'DonatoRao, ShilpaShilpaRaoDi Ruscio, FrancescoFrancescoDi RuscioSeposo, XerxesXerxesSeposoGuo, YumingYumingGuoTong, ShiluShiluTongMasselot, PierrePierreMasselotGasparrini, AntonioAntonioGasparriniSera, FrancescoFrancescoSera2024-12-102024-12-102024-12https://boris-portal.unibe.ch/handle/20.500.12422/189604Objectives While COVID-19 continues to challenge the world, meteorological variables are thought to impact COVID-19 transmission. Previous studies showed evidence of negative associations between high temperature and absolute humidity on COVID-19 transmission. Our research aims to fill the knowledge gap on the modifying effect of vaccination rates and strains on the weather-COVID-19 association. Methods Our study included COVID-19 data from 439 cities in 22 countries spanning 3 February 2020 - 31 August 2022 and meteorological variables (temperature, relative humidity, absolute humidity, solar radiation, and precipitation). We used a two-stage time-series design to assess the association between meteorological factors and COVID-19 incidence. For the exposure modeling, we used distributed lag nonlinear models with a lag of up to 14 days. Finally, we pooled the estimates using a random effect meta-analytic model and tested vaccination rates and dominant strains as possible effect modifiers. Results Our results showed an association between temperature and absolute humidity on COVID-19 transmission. At 5 °C, the relative risk of COVID-19 incidence is 1.22-fold higher compared to a reference level at 17 °C. Correlated with temperature, we observed an inverse association for absolute humidity. We observed a tendency of increased risk on days without precipitation, but no association for relative humidity and solar radiation. No interaction between vaccination rates or strains on the weather-COVID-19 association was observed. Conclusions This study strengthens previous evidence of a relationship of temperature and absolute humidity with COVID-19 incidence. Furthermore, no evidence was found that vaccinations and strains significantly modify the relationship between environmental factors and COVID-19 transmission.enCOVID-19Distributed lag nonlinear modelsHumidityMulti-Country Multi-City Collaborative Research NetworkPrecipitationSolar radiationTemperatureTime-series design600 - Technology::610 - Medicine & health300 - Social sciences, sociology & anthropology::360 - Social problems & social services500 - Science::550 - Earth sciences & geologyarticle10.48620/773513953438710.1097/EE9.0000000000000338