Outbreak of 2009 pandemic influenza A(H1N1), Los Lagos, Chile, April-June 2009

Collective Chilean Task Force for study of Pandemic Influenza A (H1N1); E Pedroni; M García; V Espínola; A Guerrero; C González; A Olea; M Calvo; B Martorell; M Winkler; M V Carrasco; J A Vergara; J Ulloa; A M Carrazana; O Mujica; J E Villarroel; M Labraña; M Vargas; P González; L Cáceres; C G Zamorano; R Momberg; G Muñoz; J Rocco; V Bosque; A Gallardo; J Elgueta; J Vega

doi:10.2807/ese.15.01.19456-en

Surveillance and outbreak reports Open Access

Like 0

Download

Outbreak of 2009 pandemic influenza A(H1N1), Los Lagos, Chile, April-June 2009
Collective Chilean Task Force for study of Pandemic Influenza A (H1N1)¹ , E Pedroni² , M García³ , V Espínola³ , A Guerrero³ , C González³ , A Olea³ , M Calvo⁴ , B Martorell⁵ , M Winkler⁵ , M V Carrasco⁵ , J A Vergara⁵ , J Ulloa⁵ , A M Carrazana⁵ , O Mujica² , J E Villarroel⁴ , M Labraña³ , M Vargas⁵ , P González⁵ , L Cáceres⁵ , C G Zamorano⁵ , R Momberg⁵ , G Muñoz⁵ , J Rocco⁵ , V Bosque⁵ , A Gallardo⁵ , J Elgueta⁵ , J Vega³
View Affiliations Hide Affiliations

Affiliations: ¹ The Ministry of Health Task Force is integrated by experts of the Ministry of Heath (Epidemiology, Health care services, Clinicians, laboratory), Scientific and medical society experts, Santiago, Chile ² Pan American Health Organization, Washington DC, United States ³ Ministry of Health of Chile, Santiago, Chile ⁴ Chilean Infectiology Society, Valdivia, Chile ⁵ Los Lagos Regional Health Office, Puerto Montt, Chile

Correspondence:
C González
Claudia.Gonzalez minsal.gov.cl
View Citation Hide Citation

Citation style for this article: Chilean Task Force for study of Pandemic Influenza A (H1N1) Collective, Pedroni E, García M, Espínola V, Guerrero A, González C, Olea A, Calvo M, Martorell B, Winkler M, Carrasco M V, Vergara J A, Ulloa J, Carrazana A M, Mujica O, Villarroel J E, Labraña M, Vargas M, González P, Cáceres L, Zamorano C G, Momberg R, Muñoz G, Rocco J, Bosque V, Gallardo A, Elgueta J, Vega J. Outbreak of 2009 pandemic influenza A(H1N1), Los Lagos, Chile, April-June 2009. Euro Surveill. 2010;15(1):pii=19456. https://doi.org/10.2807/ese.15.01.19456-en Received: 15 Oct 2009

Abstract

On 17 May 2009, the first two cases of 2009 pandemic influenza A(H1N1) were confirmed in the Metropolitan region (Santiago, Chile). On 6 June 2009, Chile reported 500 confirmed cases, seven severe and two fatal. Because six of the severe cases and the two deaths occurred in the region of Los Lagos in southern Chile, a retrospective study was conducted using data on emergency room visits as well as laboratory viral surveillance, during the period from 1 April to 31 May, in order to establish the date of the beginning of the outbreak. From 1 to 27 June, data were collected in real time, to establish the real magnitude of the outbreak, describe its transmission, clinical severity and secondary attack rates. Confirmed cases, their household contacts and healthcare workers were interviewed. This analysis showed that the outbreak in Los Lagos started on 28 April. By 27 June, a total of 14,559 clinical cases were identified, affecting mostly 5-19 year-olds. The effective reproduction number during the initial phase (20 days) was 1.8 (1.6-2.0). Of the 190 confirmed cases with severe acute respiratory infection, 71 (37.4%) presented a risk condition or underlying illness. .