After a short stint in the
private sector as Senior VP, Medicine at Becton, Dickinson & Co., Sencer, in 1982, during the development of the
AIDS epidemic in New York City, rejoined the
public sector as the health commissioner of the city, whose mayor was
Edward I. Koch. Although some appreciated his arrangement of weekly information-swapping sessions between doctors and public health officials, others, particularly those in the gay community, reprehended him for "dragging his feet". AIDS activist
Larry Kramer contended, "He and his reign accounted for one of the most disastrous experiences of public health anywhere in the world... What did he do? He didn't do anything. He had a mayor who said, 'I don't want to know,' and Sencer fell into line."
James Colgrove, however, acknowledged Sencer's "amending the city's codes so that AIDS cases were treated confidentially, defending the right of children with AIDS to attend public schools, and being an early advocate for a city-sponsored needle-exchange program". Colgrove agreed with critics that Sencer was a poor public educator. He neglected to disseminate information regarding sexual risk reduction for gay and bisexual men, and initially did not publicize that "casual contact" did not spread AIDS. Sencer also supported "free clean needles for addicts and fought to keep gay bathhouses open, believing they were an ideal place to teach safe sex". Former CDC director
Thomas Frieden called Sencer "a public health giant... And until the end he continued to be a thoughtful and vibrant member of the public health community. At the height of the
H1N1 pandemic of 2009, he was here full time, and I said, 'Can I pay you?' He said, 'No, this is a labor of love.'" ==Death==