Cuba currently exports considerable health services and personnel to Venezuela in exchange for subsidized oil. Cuban doctors play a primary role in the Mission Barrio Adentro (Spanish: "Mission Into the Neighborhood") social welfare program established in Venezuela under former Venezuelan president Hugo Chávez. Cuba also successfully exports many medical products, such as vaccines. Cuba attracts about 20,000 paying health tourists, generating revenues of around $40 million a year for the Cuban economy. Cuba has been serving health tourists from around the world for more than 20 years. The country operates a special division of hospitals specifically for the treatment of foreigners and diplomats. Foreign patients travel to Cuba for a wide range of treatments including eye-surgery, neurological disorders such as multiple sclerosis and Parkinson's disease, cosmetic surgery, addictions treatment, retinitis pigmentosa and orthopaedics. Most patients are from Latin America, Europe and Canada, and a growing number of Americans also are coming. By 1998, according to the Economic Commission for Latin America and the Caribbean, the Cuban health sector had risen to occupy around 2 percent of total tourism. Some of these revenues are in turn transferred to health care for ordinary Cubans, although the size and importance of these transfers is both unknown and controversial. At one nationally prominent hospital/research institute, hard currency payments by foreigners have financed the construction of a new bathroom in the splenic surgery wing; anecdotal evidence suggests that this pattern is common in Cuban hospitals. The Cuban Ministry of Health produces a number of medical journals including the ACIMED, the Cuban Journal of Surgery and the Cuban Journal of Tropical Medicine. MEDICC Review is an English language journal which works to bring Cuban medical and public health policy, research, programs, and outcomes to the attention of the global health community. Because the U.S. government restricts investments in Cuba by U.S. companies and their affiliates, Cuban institutions have been limited in their ability to enter into research and development partnerships, although exceptions have been made for significant drugs. The Center of molecular immunology (CIM) developed nimotuzumab, a monoclonal antibody used to treat cancer. Nimotuzumab is an inhibitor of epidermal growth factor receptor (EGFR), which is over-expressed in many cancers. Nimotuzumab is now being developed with international partners. In April 2007, the Cuba IPV Study Collaborative Group reported in the New England Journal of Medicine that inactivated (killed) poliovirus vaccine was effective in vaccinating children in tropical conditions.