key: cord-0974595-zvvwwc0r
authors: RAHAL, F.; REZAK, S.; BABA HAMED, F. Z.
title: Impact of meteorological parameters on the Covid-19 incidence. The case of the city of Oran, Algeria.
date: 2020-07-14
journal: nan
DOI: 10.1101/2020.07.10.20151258
sha: 533e699cd735ee711c7e3ffa4f28c13b2f721b93
doc_id: 974595
cord_uid: zvvwwc0r

Several studies have confirmed the impact of weather conditions on the evolution of the Covid-19 pandemic. We wanted to verify this phenomenon in the city of Oran in Algeria, which experienced its first case of Covid19 on March 19, 2020. The data studied are the new Covid19 cases, the average, minimum and maximum temperatures, as well as the relative humidity rate. A first analysis of the data with a Spearman rank correlation test did not yield significant results. Taking into account the average incubation period to adjust the data made it possible, during a second analysis, to show that the minimum temperature is significantly correlated with the new cases of Covid19 in Oran. This study can help establish prevention policies against Covid19, especially during fall in temperatures in autumn and winter.

The transmission of viruses can be impacted by several factors, including climatic conditions such as temperature and humidity as well as population density (Dalziel et al., 2018) . However, there is not yet enough time to fully understand the influence of meteorological parameters on the spread of the Covid19 virus. But already, several research works have been carried out on this field (Tosepu et al., 2020; Ma et al., 2020; Qi et al., 2020; Şahin, 2020) since the World Health Organization (WHO) declared that the Covid19 pandemic is a Public Health Emergency of International Concern (PHEIC), on January 30, 2020. Algeria, like other countries in the world, has not escaped this Covid pandemic19 (Boudrioua et al., 2020) . The first case reported on February 25, 2020, was imported from Italy (Hamidouche, 2020) . In order to limit exposure to the virus, partial containment measures were imposed on certain cities that reported the highest number of contaminated cases. More and more people are invited to isolate themselves or to quarantine themselves, they only leave their homes to buy essential items such as food and medicines (Moussaoui et al., 2020) .

The city of Oran, the second largest city in Algeria, registered on March 19, 2020 its first case of Covid19. Figure 1 shows the progression of proven cases from Covid19 to Oran since that date. Several models can help monitor an outbreak and predict its evolution. The most classic being the SIR model (Roques et al., 2020) which is based on the work of the theory of Kermack et al., 1927 . We carried out a simulation of the SIR model for the period from 03/19/2020, date when the first case was registered in Oran until 04/04/2020, date of application of the strictest partial containment in Oran. The result of the simulation gives a basic reproduction number R0 = 2.125638 for the abovementioned period. Thus, at the start of the outbreak, a person infected with Covid19 could infect more than 2 people. This situation could have caused an exponential spread of the virus after 02 weeks as shown by the simulation of the SIR model presented in Figure 2 . We can also see that this reproduction of the virus was probably slowed down by the sanitary and containment measures taken by Public powers. Indeed, containment is a barrier measure used to break the chains of virus transmission during an outbreak (Badsi et al., 2020) . 

The Oran region is characterized by a semi-arid climate (Bounoua et al., 2009) with annual rainfall less than 330 mm, occurring mainly between the months of October and May; average monthly temperatures vary between 5 ° and 17 ° C in winter and 16 ° and 31 ° C in summer (WMO, 2020). The city of Oran is located in the northwest of Algeria, bordered by the Mediterranean Sea to the north and the Sebkha to the southwest as shown in Figure 3 . Bukhari et al., 2020 have shown that low temperature and humidity levels are key variables in determining the transmission of Covid19. Therefore, it is interesting to study this phenomenon for the region of Oran. For this study, we used the meteorological data recorded, during the months of April, May and June, at the meteorological station of Es Senia concerning minimum temperature (° C), average temperature (° C), maximum temperature (° C), and the relative humidity (%). Data on new Covid19 cases in Oran are from the MSPRH, 2020.

A Spearman rank correlation test was used to analyze this data. The table 1 shows the obtained coefficients . A 6-day shift in weather data from Covid19 data found a significant correlation between new Covid19 cases and minimum temperatures as shown in Table 2 . 

Even if the Covid19 pandemic in Oran seems relatively under control, the significant correlation between the minimum temperatures and the spread of the virus should alert health authorities to the risk of the epidemic worsening when the temperatures drop. Given that meteorological parameters have a significant and consistent distribution of the seasonal behavior of respiratory viruses (Sajadi et al., 2020) , it is desirable that the fight against Covid19 be intensified during the summer in order to anticipate a possible upsurge contaminations that could appear in autumn and winter.

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