CDC has warned the country risks losing its measles elimination status if the outbreak, which began on October 2018 in New York state, continues until October 2019

The United States recorded 21 new measles cases last week, raising the total number of cases for the year to 1,203 across 30 states in the worst outbreak of the virus since 1992, federal health officials announced on Monday.

The U.S. Centers for Disease Control and Prevention said there had been a 1.8% increase in the number of cases of the highly contagious and rarely deadly disease.

In a warning that the outbreak is slowing, the CDC in recent weeks has reported smaller increases in the number of measles cases, compared with surges of dozens of cases recorded per week earlier this year.

Failure to vaccinate poses a public health risk to vulnerable people unable to receive the vaccine, health officials have warned.

The disease was declared eliminated in the United States in 2000, meaning there was no constant transmission of the disease for a year. However, virus cases increase and spread via travelers coming from countries where measles is common.