Background: In April 2009, the 2009 pandemic influenza A (H1N1)(2009H1N1) virus was detected in Southern California; shortly thereafter, the United States declared a public health emergency and initiated influenza prevention campaigns. Influenza vaccination rates are unknown among U.S.–Mexico border crossing populations. Because 250 million persons enter the United States through the U.S.–Mexico land border each year, land ports of entry (POEs) provide a venue for assessing whether influenza prevention campaigns are reaching mobile populations.
Objectives: To assess border-crosser influenza awareness and adherence with public health recommendations regarding influenza at the beginning and the end of the 2009–2010 influenza season.
Methods: We administered a cross-sectional survey to pedestrian border crossers to characterize knowledge, attitudes, and practices (KAP) regarding the 2009H1N1 vaccine in San Diego, CA, and El Paso, TX, November 2009 and March/April 2010. We conducted multivariable logistic regression to determine factors associated with 2009H1N1 vaccination acceptance.
Results: A total of 1,112 border-crossers were interviewed (nNov= 553, nMar/Apr= 559). Most respondents (81.6%) were born in Mexico. Most respondents (95.6%) received influenza health messages. Persons primarily learned about influenza on television (87.5%) and radio (48.4%). Only 7.4% saw messages at POEs. During fall 2009, 1.8% reported having received the 2009H1N1 vaccine, compared to 23.3% during spring 2010. Of 124 respondents who reported having a health condition or risk factor, 29.8% were vaccinated against 2009H1N1 in March/April 2010. Factors associated with 2009H1N1 vaccination included receiving a seasonal flu vaccine in the past, spending most of the time in Mexico, and having health insurance coverage.
Conclusions: U.S.–Mexico border crossing populations did receive influenza prevention messages, mostly from mass media; a small percentage saw messages at POEs. 2009H1N1 vaccination coverage among this mobile Hispanic population was comparable to U.S. rates. Ongoing surveillance of border crossers is needed to determine whether POEs might be useful sites for outreach and vaccination interventions.