Messonnier began her career in public health in 1995 as an epidemic intelligence service officer in the National Center for Infectious Diseases, a program of the Centers for Disease Control and Prevention. During her tenure at the CDC, she led the Meningitis and Vaccine Preventable Diseases Branch in NCIRD's Division of Bacterial Diseases from 2007 to 2012. She also served as the deputy director of NCIRD from 2014 to 2016 before becoming director of the center on April 4, 2016. During the course of her career, Messonnier notably worked on the 2001 anthrax attacks response, serving as co-leader of the anthrax management team and vaccine working group. She also played a leading role developing a low-cost meningococcal meningitis vaccine to prevent an emerging epidemic in Africa, known as MenAfriVac, in 2010. She has also worked on communications strategies to promote the use of vaccines to prevent the emergence of disease outbreaks.
Since January 2020, Messonnier has been helping lead the CDC efforts to address and combat the emerging threat of COVID-19, the disease caused by the novel coronavirus. When 195 Americans were evacuated out of Wuhan because of the virus, the CDC moved to quarantine all of them, with Messonnier noting: "While we realize this is an unprecedented action, this is an unprecedented threat." In a February 25 press briefing at the White House, Messonnier warned of the impending community spread of the virus in the United States, stating: "Disruption to everyday life might be severe." Following her comments during the February White House press briefing, she did not appear again at the briefing and there was speculation that Messonnier had been "silenced" for her comments stressing the growing urgency of the COVID-19 pandemic in the United States. On February 28, she said that the U.S. "acted incredibly quickly before most other countries. Aggressively controlled our borders and we were able to slow the spread into the United States....We have been testing aggressively." While Messonnier has no longer appeared in White House briefings, she has continued giving regular CDC briefings, which have been broadcast to the public, and she has made public appearances in All Things Considered on NPR. She continues to be a public source of reliable information on the pandemic. On March 9, she cautioned those who were at high risk of severe illness, including the elderly and people with pre-existing conditions. These cautionary measures included stocking up on groceries and medications as well as preparing to shelter in place for the foreseeable future. She noted that it was possible that the virus could continue to circulate into next year and that state and local public health officials would begin working to mitigate the spread of the disease and minimize the growing burden on healthcare workers who would soon be dealing with high case loads. She has also addressed concerns around the CDC and FDA's failure to get working COVID-19 testing kits into the hands of public health officials to enable better containment of the disease and for mitigation of its spread. On January 21, 2020, she had announced that the CDC had finalized its own COVID-19 test. On February 5, the CDC began distributing diagnostic tests to public-health laboratories, however, several of those tests had contaminated reagents, rendering them useless, and leading to a major gap in fighting the outbreak. The situation was exacerbated by FDA-imposed regulations on testing, making it difficult for independent development of COVID-19 tests to fill the CDC's distribution gap.
Personal life
Messonnier is married to Mark L. Messonnier. She is the sister of Rod Rosenstein.
Awards, honors, and decorations
2000: Centers for Disease Control and Prevention, Iain C. Hardy Memorial Award
