Mexico have suspended infant vaccinations temporarily after two babies died and 29 others fell seriously ill following routine vaccinations they had been given in southern Mexico.
The babies had received vaccinations for tuberculosis, rotovirus and Hepatitis B.
The cause of the adverse reactions is not known, the institute said Sunday.
The institute said it stopped vaccines nationwide on Saturday as a precaution.
Rev. Marcelo Perez, a Roman Catholic priest, told The Associated Press that families of the babies said they became sick within hours.
The adverse reactions started Friday and the babies were taken to a hospital in Simojovel, Chiapas, where 93 percent of the people live in poverty, according to government statistics.