If both the U.S. and Slovak social security systems cover a worker’s employment or
self-employment, the agreement provides that beginning May 1, 2014, only one country’s
system will cover the worker’s employment or self-employment. The agreement does not
affect a worker's coverage prior to that date. If a worker had dually covered earnings
before May 1, 2014, those earlier earnings were and would continue to be subject to
social security contributions in both countries.