Venezuela kicked off a campaign Sunday to vaccinate 3.8 million residents by May 31.
The project, carried out by the Panamerican Health Organization (OPS), will provide 800,000 doses more than last year.
Medical workers will carry out house-to-house visits in difficult-to-access poor communities and indigenous areas, to ensure that children and families in those zones are protected against 14 illnesses as part of an immunization scheme.
The emphasis in the project is on children between one and nine years of age, as well as the elderly, and will include vaccines against tuberculosis, hepatitis B, and meningitis.
As well as the house calls, the organization has set up 5,957 immunization points, where children, young people and the elderly can be seen free of charge, and where information will also be provided about staying healthy.
An estimated one in five children around the world are not vaccinated.