LONDON — British Prime Minister Boris Johnson has tested negative for the coronavirus, but will complete 14 days of self-isolation because of contact with an infected person.

Johnson’s office says the prime minister was tested using a lateral flow test — a quick test that doesn’t need to be processed in a lab. The tests are not widely available in the U.K., but the government says staff in the prime minister’s office could get them as part of a pilot project.

Johnson was told to self-isolate on Sunday after a lawmaker with whom he had met three days earlier tested positive for the coronavirus. The prime minister says he has no symptoms and will continue to lead the government, holding meetings using videoconferencing.

Government rules say people in close contact with an infected person must quarantine for two weeks.

Johnson was seriously ill with the coronavirus in April, spending three nights in intensive care. People who recover from the virus are thought to have some immunity, but it’s unclear how long it lasts. There have been a small number of confirmed cases worldwide of people becoming re-infected with the virus.