No matter how many weeks go by, the pandemic remains full of mysteries that are reluctant to unravel. One of the most complex to answer (due to the lack of rigorous data and analysis) is what happened in late February and early March in Europe. The information is contradictory: researchers finding the virus in sewage from March 2019, cases from January and February diagnosed retrospectively, protocols too strict to detect what was happening and, finally, the evidence that Europe became the epicenter of the epidemic around the same time.
To shed some light, a team of researchers from the Ramón y Cajal, 12 de Octubre, Gregorio Marañón and La Princesa hospitals together with the Public Health Service of the Community of Madrid have analyzed archival respiratory samples collected between December 15, 2019 and March 1, 2020. The idea is that, By studying cases of influenza and unknown pneumonia, you could find out indirectly when the virus arrived and how it spread by the Community of Madrid (and the rest of Spain).
Thousands of archived cases help us better understand what happened
They have done? Researchers have collected 1,350 respiratory samples. On the one hand, 642 samples were from the influenza surveillance sentinel network and upon passing the COVID tests all were negative. On the other hand, 669 samples from the emergency department and 39 from intensive care units were analyzed; all of them were patients with atypical pneumonia. Only two cases of the ER samples were positive: two samples received during the first week of March.
What does it mean? Although the final work will be presented at the I National Covid-19 Congress and has not yet been published, the data that we have had access to suggests that, surprisingly enough, the SARS-CoV-2 virus did not circulate (or made residual) by the country in the weeks leading up to the start of the pandemic. At least, there is no sample of suspicious patients at our disposal as, on the other hand, would be reasonable to expect if community transmission had been as widespread as we feared at the time.
And so? The data suggests that the accumulation of cases in March 2019 were due to various cases that were introduced almost simultaneously in the autonomous community. However, the study only gives a partial view of the problem. Very valuable, but partial. In the coming months we will be able to see in more detail how the virus moved through Europe and to what extent these outbreaks were, in fact, as simultaneous as they now seem.
Images | Hospital Clinic and Malopez 21