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.

Commerce Secretary Wilbur Ross said in a statement Saturday the agency may look at extending its response collection operations past the current July 31 end date. Ross said at a House hearing last week that the agency has a 24/7 “fusion center” to grapple with problems like the coronavirus pandemic.

“As we continue to assess the current situation, we will always make decisions that ensure the health and safety of our staff and the public in consultation with public health authorities,” he said.

Ross, whose department oversees the Census Bureau, emphasized the ease of responding to the census this year. People can respond to the census online, over the phone or by paper. The federal government uses census results to divvy up congressional seats as well as about $1.5 trillion in annual spending.

Democrats in Congress asked Ross and Census Bureau Director Steven Dillingham to address issues presented by the pandemic at a hearing and in a series of letters last week.

The agency has not made any statements about changes to its plans for the full door-knocking operation, which is set to start in May. Census Bureau plans would have the agency hire between 350,000 and 500,000 temporary staff to head out to homes that did not respond on their own in the initial phase.