The virological diagnosis performed well with the surveillance methods more specific to the 2009-H1N1 influenza A virus. It should be noted that diagnosis was first performed at the Institute Malbran, after which another 18 laboratories were enabled to perform real-time (RT)-PCR, three of which are the National Influenza Center of the WHO, which also performed culture and serology for this virus. The percentage of positivity for the new virus was 43.3 percent (8,851/20,409). In the weekly distribution, the circulation of respiratory syncytial virus (RSV) is seen during the whole period but the peak of diagnosis occurred in weeks 25 and 26 for the new virus (Figure A13-9).

Figure A13-10 illustrates that RSV is dominant for children up to age one; however, the 2009-H1N1 influenza A virus was dominant for all other age groups.

The age distribution of cases of SARI showed that the largest group affected were the 0- to 4-year-olds, but we must consider that some of these correspond to cases of RSV observed in the laboratory diagnosis. The hospitalization rate was 23.4 per 100,000 inhabitants (Figure A13-11).

The time distribution for hospitalized patients shows a peak in late June, about a week after the peak of the ILI epidemic curve, and the beginning of severe cases shifted by 15 days for ILI during the period in which cases were given treatment and prophylaxis was given to their contacts. As of early July, the intensity

FIGURE A13-9 Distribution of respiratory viruses by epidemiological week, Argentina 2009.

SOURCE: Ministry of Health National Surveillance System.