The Texas health department on Tuesday reported 279 measles cases in the state, an increase of 20 cases from its previous count.
According to the Texas Department of State Health Services, cases in Gaines county, the center of the outbreak, rose from 174 to 191.
The department added that hospitalizations rose to 36 from 34 as of March 14.
It classified 277 patients as unvaccinated or unknown, or people with no documented doses of measles vaccine more than 14 days before symptoms appeared.
It was gathered that in New Mexico, cases rose from 33 to 35 on Friday, including two cases in Eddy County and the rest in Lea County, which is adjacent to Gaines County.
The Centre for Disease Control, CDC, has said that the measles, mumps and rubella, MMR, vaccine is the most important tool for preventing measles.