Revista de Salud Pública
Print version ISSN 0124-0064
NUNEZ, Lilian M et al. Chronology of a pandemic: the new influenza A (H1N1) in Bogota, 2009-2010. Rev. salud pública [online]. 2011, vol.13, n.3, pp. 480-491. ISSN 0124-0064. http://dx.doi.org/10.1590/S0124-00642011000300010.
Objectives Describing the behaviour of the A H1N1/09 virus related to time, age and gender in patients having suspected infection, medical health care and laboratory diagnosis. Method This was a descriptive and retrospective study of patients diagnosed as having the influenza A H1N1/09 virus between April 2009 and July 2010 by the Bogotá Public Health Laboratory. Results The first cases of A H1N1/09 virus were confirmed since week 17, 2009; positivity increased gradually, reaching maximum expression between weeks 31-36, 2009 (43 % to 53 %) and decreased during the 37th week. The age groups most affected were 6-15 years (35.4 %) and 16-25 years (28 %) (p=0.0044); the lowest percentages were found in children aged less than 1 year (8.7 %) and people older than 65 years (7.2 %) (Chi 1.98, p=0.119). The gender ratio was similar: female (18.6 %) and male (17.6 %) (Chi 1.82, p=0.1768). Conclusions There was a significant increase in influenza A cases during 2009. However, this did not alter the behaviour of the endemic respiratory syncytial virus; on the other hand, the H1N1/09 subtype replaced the seasonal virus circulating amongst the population of Bogotá, similarly affecting men and women, mainly young adults. The highest prevalence of cases occurred between August and September 2009.
Keywords : Human influenza; influenza A virus; respiratory tract infection; epidemiological surveillance; respiratory syncytial viruses; public health.