E/C.12/2017/1 prejudice to the possibility for the State to order that they leave the territory, the very presence of such migrants under its jurisdiction imposes on the State certain obligations, including of course the primary obligation to acknowledge their presence and the fact that they can claim rights from national authorities. 12. In its general comment No. 14 (2000) on the right to the highest attainable standard of health, the Committee recalled that States parties have a duty to respect the right to health by ensuring that all persons, including migrants, have equal access to preventive, curative and palliative health services, regardless of their legal status and documentation (para. 34). The Committee is aware that migrants face specific obstacles in this regard, as documentation may be required from those seeking access to health care. Migrants, particularly those who do not speak the language of the host country, may not be aware of their entitlements. Migrants in an irregular situation may also fear being detained for deportation, particularly in countries where public officials have a duty to report on irregular migrants. In addition to ensuring access to health care without discrimination, strict walls should exist between health-care personnel and law enforcement authorities, and adequate information should be made available in the languages commonly spoken by migrants in the host country, in order to ensure that such situations do not result in migrants avoiding seeking and obtaining health care. 13. In its general comment No. 23 (2016) on the right to just and favourable conditions of work, recognized under article 7 of the Covenant, the Committee identified migrant workers as a group whose rights were particularly at risk. It noted that such workers, “in particular if they are undocumented, are vulnerable to exploitation, long working hours, unfair wages and dangerous and unhealthy working environments” (para. 47 (e)). It listed a number of factors that may increase their vulnerability, including situations where the employer has control over the migrant worker’s resident status or that tie migrant workers to a specific employer; the inability of the workers concerned to speak the national language(s); the fear of reprisals from employers; and the fear of eventual expulsion if they seek to complain about working conditions. It follows that, in addition to laws and policies having to ensure that migrant workers enjoy treatment that is no less favourable than that of national workers in relation to remuneration and conditions of work, specific measures of protection may have to be adopted for the benefit of undocumented workers, to ensure that any abuse of their situation of vulnerability is effectively addressed and that they do not fear filing complaints with the competent authorities. 14. Similar concerns arise as regards the right to housing. The Committee has repeatedly found that migrants are housed in substandard conditions, sometimes in geographically segregated areas. Its concerns were echoed in this regard by the Committee on the Elimination of Racial Discrimination which, in its general recommendation No. 30 (2004) on discrimination against non-citizens, urged States parties to “remove obstacles that prevent the enjoyment of economic, social and cultural rights by non-citizens, notably in … housing” (para. 29) and to “guarantee the equal enjoyment of the right to adequate housing for citizens and non-citizens, especially by avoiding segregation in housing and ensuring that housing agencies refrain from engaging in discriminatory practices” (para. 32). 15. In its general comment No. 19 (2007) on the right to social security, the Committee recalled that migrants should be entitled to have access to “non-contributory schemes for income support, affordable access to health care and family support” (para. 37). Restrictions on access to such schemes, including the requirement of a qualification period, should be reasonable and proportionate. The extension of social security contributory benefits to asylum seekers and undocumented migrants poses specific challenges, however, since the precarious (and sometimes temporary) situation of such groups may make it difficult for them to be integrated into such schemes. The Committee notes, however, that even when they are irregularly employed, often by unscrupulous employers seeking to reduce costs by not paying social security contributions, workers belonging to these categories do contribute to the financing of the social security system by paying indirect taxes. The inability of undocumented workers to obtain social security benefits increases their vulnerability and their dependence on their employers. 16. The Committee recognizes that the vulnerability of women and girl migrants and refugees to trafficking and other forms of gender-based violence and exploitation increases 4