US-Mexico binational COVID-19 cases in southern California border counties, California, February-June 2020.

Background: COVID-19 has had a significant public health impact on both the United States and Mexico. Cross-border mobility between southern California and Mexico raises questions of transmission trends between these jurisdictions. The objective of this project was to describe binational cases amongst California US-Mexico border county COVID-19 cases and compare incidence trends to cross-border Mexico jurisdictions. Methods: Interview data from persons with confirmed SARS-CoV-2 infections in San Diego County, CA and Imperial County, CA from February to June 2020 were reviewed for binational cases; demographics and connection to COVID-19 outbreaks were assessed. Graphs of COVID-19 incidence in San Diego County and Imperial County were compared to incidence graphs in cross-border Mexico jurisdictions of Tijuana and Mexicali. Results: Persons with COVID-19 and a binational case were older, more likely to be Hispanic, and reside in a border ZIP code than those without. Binational cases were a small proportion and tracked with overall cases during the study period. Conclusions: Binational cases had different trends than non-binational cases of SARS-CoV-2 in San Diego and Imperial counties from February to June 2020. Findings could inform SARS-CoV-2 mitigation strategies specific to the US-Mexico land border, particularly recommendations regarding cross-border land travel.

Acute viral hepatitis in the United States-Mexico border region: data from the Border Infectious Disease Surveillance (BIDS) Project, 2000-2009.

Little is known about the characteristics of acute viral hepatitis cases in the United States (US)-Mexico border region. We analyzed characteristics of acute viral hepatitis cases collected from the Border Infectious Disease Surveillance Project from January 2000-December 2009. Over the study period, 1,437 acute hepatitis A, 311 acute hepatitis B, and 362 acute hepatitis C cases were reported from 5 Mexico and 2 US sites. Mexican hepatitis A cases most frequently reported close personal contact with a known case, whereas, US cases most often reported cross-border travel. Injection drug use was common among Mexican and US acute hepatitis B and C cases. Cross-border travel during the incubation period was common among acute viral hepatitis cases in both countries. Assiduous adherence to vaccination and prevention guidelines in the US is needed and strategic implementation of hepatitis vaccination and prevention programs south of the border should be considered.

Understanding knowledge, attitudes, and behaviors related to influenza and the influenza vaccine in US-Mexico border communities.

Hispanics are less likely to receive the influenza vaccine compared to other racial and ethnic groups in the US. Hispanic residents of the US-Mexico border region may have differing health beliefs and behaviors, and their cross-border mobility impacts disease control. To assess beliefs and behaviors regarding influenza prevention and control among border populations, surveys were conducted at border clinics. Of 197 respondents, 34 % reported conditions for which vaccination is indicated, and travel to Mexico was common. Few (35 %) believed influenza could make them 'very sick', and 76 % believed they should take antibiotics to treat influenza. Influenza vaccine awareness was high, and considered important, but only 36 % reported recent vaccination. The belief that influenza vaccination is 'very important' was strongly associated with recent vaccination; "Didn't think about it" was the most common reason for being un-vaccinated. Misconceptions about influenza risk, prevention and treatment were common in this Hispanic border population; improved educational efforts and reminder systems could impact vaccination behaviors.