SPECIAL FEATURES:METHODS Social Network Analysis to Evaluate Nursing Interventions to Improve Self-Care Margarita Ma ´ rquez-Serrano, M.Sc., 1 Xochitl Gonza ´ lez-Jua ´ rez, M.P.H., 2 Lorena E. Castillo-Castillo, M.P.H., 3 Leonel Gonza ´ lez-Gonza ´ lez, M.Sc., 4 and Alvaro J. Idrovo Ph.D. 1 1 Center for Health Systems Research, National Institute of Public Health, Cuernavaca, Morelos, Mexico; 2 Ministry of Education, Culture and Social Security, State of Mexico (SECyBS), Villa Guerrero, Estado de Me ´xico, Mexico; 3 Student’s Affairs Department, National Institute of Public Health, Cuernavaca, Morelos, Mexico; and 4 Center of Information to Decisions in Public Health, National Institute of Public Health, Cuernavaca, Morelos, Mexico Correspondence to Alvaro J. Idrovo, Center for Health Systems Research, National Institute of Public Health, Avenida Universidad 655, Colonia Santa Marı ´a Ahuacatitla ´n, CP 62100, Cuernavaca, Morelos, Mexico. E-mail: javier.idrovo@insp.mx ABSTRACT Objective: To explore the impact of an educational intervention for self-care of elders on their knowledge of acute respiratory infections and its incidence within their social net- works. Method: The intervention was based on seven educational sessions with elders from Jiute- pec (Morelos, Mexico) conducted between September 2009 and January 2010 in the context of the influenza A(H1N1) pandemic. Egocentric social network analysis was used to explore the transmis- sion of knowledge within elders networks. Results: Knowledge of the correct use of antibiotics increased (p < .05). The total network was composed of 94 individuals, of which 22 presented with respiratory infection during the 4.5 months of follow-up. The measurements of infected individuals were in a degree similar to those not infected (p > .05). No differences in incidence were observed with respect to gender, kinship or sub-networks. Discussion: Elders increased their self-care and knowledge, but this did not decrease the incidence of cases in their social networks. This may be due to isolation and lack of recognition and credibility among close friends and relatives. Social network analysis can be used to understand and evaluate nursing self-care interventions. Key words: aging, epidemiology, Latinos, pandemic, socioeconomic factors, surveillance. Several studies confirm that nursing interventions to transmit knowledge are effective in increasing self-care practices, modifying unhealthy behaviors, and diminishing the occurrence of diseases (Kreu- len & Braden, 2004). However, the conventional approach (instructor and participant only) is poten- tially only effective for those who participate directly in the intervention, forgetting the partici- pants’ family, friends, and neighbors. These persons may be intervened indirectly through social net- works, but public health nurses may not be aware of or have developed a method to access these indi- viduals. Understanding this indirect transmission of knowledge is highly relevant in developing coun- tries where there are not enough public health nurses, and their interventions need to reach all community members. This situation occurred dur- ing the influenza A(H1N1) outbreak in Mexico. The appearance of the A(H1N1) epidemic in 2009 was a challenge for the Mexican health sys- tem (Idrovo, Ferna ´ndez-Nin ˜o, Bojo ´rquez-Chapela, & Moreno-Montoya, 2011), in spite of the prepara- tion initiated several years earlier (Mensua, Mou- nier-Jack, & Coker, 2009). Various efforts were quickly implemented to decrease contagion among the population. In general, the community outreach 361 Public Health Nursing Vol. 29 No. 4, pp. 361–369 0737-1209/© 2012 Wiley Periodicals, Inc. doi: 10.1111/j.1525-1446.2012.01014.x