The Census Bureau will delay some of its 2020 census operations to help prevent the spread of the novel coronavirus, agency officials said over the weekend.

The agency kicked off its count last week with mailers encouraging millions of households to respond to the census online. More than 3 million people have responded already, Census Bureau spokesman Michael Cook said.

But the coronavirus pandemic will push back by several weeks on-the-ground outreach and canvassing work, Cook said. The agency has a $2 billion contingency fund to handle any further disruptions to the count.

The agency originally planned to open its “Mobile Questionnaire Assistance Centers” at the end of March and begin early door-knocking in April. Cook said the agency will delay the questionnaire assistance to the second week of April. The early door-knocking will start toward the end of April.

College students who have left their campuses due to closures or due to the coronavirus will still be counted at their campus housing, Cook said. Additionally, universities that had already decided how they wanted their students counted will now be given a chance to change that decision.