Besides the climate model, other variables driving the COVID-19 spread in Brazil.

We have read with great interest the study by Auler et al. (2020), about the influence of climate on COVID-19 spread. The authors considered data from the five most affected cities by the current pandemic in Brazil. The authors used meteorological data from 13th of March to 17th of April 2020 and analyzed weather conditions such as temperature, relative humidity and rainfall against variables like number of cumulative cases, new daily cases and contamination rate to build their study model. This study is elegant and adds important information to the behavior of the new coronavirus in Brazil.

The study model and data analysis are well-performed, and although the authors found that temperature and relativity humidity influenced the COVID-19 dissemination, other variables, such as social distancing, population testing, hand wash (Giordano et al., 2020) and rational use of face mask were not part of their study model (Feng et al., 2020). We understand that these variables not included in the model are not always easy to access and did not compromise the great contribution made by the authors. Brazil is a continental country with large disparity between cities and regions, with massive differences from socioeconomic to human development.

The first official case of COVID-19 in Brazil was reported in 26th February 2020 in the city of São Paulo and 8 days later (5th March 2020) the first case in Rio (Wikipedia, 2020a). The outbreak of the COVID-19 pandemic disseminated not only the life-threatening virus, but also significant economic issues worldwide. Since the virus arrived in Brazil, politicians started to diverge from health policies. In this short time, the country watched the change of two different Ministers of Health (Wikipedia, 2020b). Today, when this text is being written, there is no Ministry of Health to guide public health polices, but a non-medical general of the Brazilian army was guided to the position as the interim Ministers of Health. Unfortunately, the Brazilian president constantly ignores the main recommendation of the WHO to tackle the dissemination of SARS-CoV-2 that is social distancing and refers to the COVID-19 as a “little flu”. On the other hand, the governors of the state of Rio de Janeiro and São Paulo, among others, are reinforcing social distancing in their state (Wikipedia, 2020b). This dispute was taken to the Supreme Court, which reinforced the authority of cities and states to define local measures of social distancing, quarantine, prohibition of activities and definition of essential services (Federal, 2020).

The COVID-19 pandemic started in Wuhan, China and spread worldwide. The cities of São Paulo and Rio de Janeiro were the 2 first cities to report cases in Brazil, which is possibly explained by their importance in commercial aviation, responsible for almost 80% of the weekly international seats of the country, 62.27% and 17.1% respectively (based on data from November 2019 of the National Civil Aviation Agency of Brazil – ANAC) (Regis, 2020). Since the cases started to spread in these cities, uncoordinated measures of social distancing were gradually implemented across the country, in despite of the divergences between the president and governors (Wikipedia, the free encyclopedia, 2020a, Wikipedia, the free encyclopedia, 2020b).

Brasilia showed the first case in 7th March and its history of the pandemic was marked by the trip of the Brazilian president to USA between 7 and 10 of March, where 16 out of 22 of the president official team got infected (Paraguassu and Boadle, 2020). After that, Brasilia, the center of the Brazilian politics and the country's capital, implemented measures to restrain the virus. On the other hand, the first case in Manaus was reported in 15th of March and 2 days after Fortaleza confirmed its first case (Wikipedia, 2020a). This study started to record the data 2 days before Manaus and 4 days before Fortaleza confirmed their first cases. Taken together, we can assume that these cities were on different stage of the epidemic curve and local public policies to restrain the virus (Vally, 2020). Since the 5 cities were chosen based on the number of cases in 13th April, we suppose that differences between the stage of the pandemic in each city could cause some influence on the spread of the virus.

Other important variables not included in the data analysis were appropriately declared by the authors as study limitations. The study limitation brought us some reflections. Unfortunately, the cities of Fortaleza and Manaus had more difficult to acquire tests and many cases were confirmed later, while the disease was spreading through the population, resulting in a delay to identify cases and implement measures to face the pandemic and creating population awareness. Manaus and Fortaleza are in less developed regions, have lower human development index (HDI) and poor sanitation than the other 3 cities (IBGE, 2020), variables that could impact the SARS-CoV-2 transmission rate (Giordano et al., 2020).

Although we suppose that the absence of few variables could mask the effect of the meteorological conditions on COVID-19 spread observed in the study by Auler et al. (2020), the authors have made an extraordinary contribution by showing the opposite, a new perspective about the new coronavirus spreading in Brazil. Winter viruses are known for being more stable and spread better in cold and low humidity (20–50%) places than those found in most cities in Brazil. Indeed, the SARS-CoV-2 is quickly spreading across the whole country regardless the weather condition and, unfortuantely, Brazil is on the way to become the new epicenter of the COVID-19 pandemic in the world.

Credit author statement

Ribeiro, A.L.R: Conceptualization, Writing - Original Draft, Writing- Reviewing and Editing. Sousa, N.W.A.: Conceptualization, Writing - Original Draft. Carvalho, V.O.: Conceptualization, Writing - Original Draft, Writing- Reviewing and Editing.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.