FRAMINGHAM — Sam Wong, director of the city's Department of Public Health for three-and-a-half years, and who guided the local response during much of COVID-19 pandemic, is resigning today, city officials say. Wong had been on leave since Jan. 1, citing health reasons. He officially submitted his resignation on Wednesday, officials said in a press release. “When I joined Framingham in August 2017, I came in at a time when the Department needed a complete overhaul,” Wong said in a statement. “I’m proud of the team and Department that I have built and believe I’m leaving the City in capable hands.”