Expected Impact of COVID-19 Outbreak in a Major Metropolitan Area in Brazil

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Expected impact of COVID-19 outbreak in a major metropolitan area in Brazil – Supporting information

Estimate of the basic reproduction number R0

A revision of different estimations of the basic reproduction number R0 for COVID-19 available in the literature are given in [1]. The value reported are given in Table 1.

Table 1. Reported values for R0. 1.95 2.2 2.2 2.24 2.5 2.55 2.68 2.9 2.92 3.11 3.58 4.08 6.47 6.49

Considering the discussion on the paper relative to the values of R0 in the beginning of the outbreak, we consider the values 6.47 and 6.49 as overestimated and discard them. We determine the average and its 95% confidence interval for Ro using the empirical bootstrap technique, with result of 2.74 (2.47, 3.03).

Population in the metropolitan area of São Paulo

As explained in the main text, the population in each group used in our work was obtained from publicly available data of the 2010 Brazilian official census, with a linear correction by the estimated population growth in São Paulo from 2010 to 2019, except for ages from 0 to 1 year of age, where the actual population is determined from birth data [2, 3]. The metropolitan area in our study is formed by the following localities: São Paulo, Arujá, Biritiba-Mirim, Ferraz de Vasconcelos, Guararema, Guarulhos, Itaquaquecetuba, Mogi das Cruzes, Poá, Salesópolis, Santa Isabel, Suzano, Caieiras, Cajamar, Francisco Morato, Franco da Rocha, Mairiporã, Barueri, Carapicuíba, Itapevi, Jandira, Osasco, Pirapora do Bom Jesus, Santana de Parnaíba, Diadema, Mauá, Ribeirão Pires, Rio Grande da Serra, Santo André, São Bernardo do Campo, São Caetano do Sul, Cotia, Embu, Embu-Guaçu, Itapecerica da Serra, Juquitiba, São Lourenço da Serra, Taboão da Serra and Vargem Grande Paulista. The estimated population in each group is given in Table 2.

Table 2. Estimated population in the metropolitan area of São Paulo in each age group considered in our study. Age group Population 0–9 2983907 10–39 11009702 40–49 2965179 50–59 2243257 60–69 1285473 ≥70 998712 Total 21486230

Transmission probability Pc

The normalized histogram for the values of the probability of transmission Pc per physical contact is show in Fig 1, for 100 000 Monte Carlos realizations (see main text). It is well fitted by

March 12, 2020 1/2 a log-normal distribution, with mean 0.21 and 95% confidence interval (0.08, 0.75). The Median and inter-quartile interval from a bootstrap analysis are 0.148 and (0.106 ,0.247), respectively.

Fig 1. Normalized histogram for the value of the parameter Pc obtained from a Monte Carlo analysis with 100 000 realizations.

0 0 0.2 0.4 0.6 0.8 P c

References

1. Liu Y, Gayle AA, Wilder-Smith A, Rockliöv J. The reproductive number of COVID-19 is higher compared to SARS coronavirus. Journal of Travel Medicine - Accepted for publication. DOI: 10.1093/jtm/taaa021.

2. Instituto Brasileiro de Geografia e Estatística (IBGE). https://cidades.ibge.gov.br/brasil/sp/sao-paulo/panorama 3. http://dive.sc.gov.br/index.php/sistemas-de-informacao/sistemas/pagina-sinasc.

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