Circulating vaccine-derived poliovirus type 2 (cVDPV2) – Algeria

In recent years, Algeria has faced challenges related to circulating vaccine-derived poliovirus type 2 (cVDPV2), a rare but significant public health concern. cVDPV2 emerges in communities with low immunization coverage, where the weakened virus strain from the oral polio vaccine (OPV) can mutate and regain neurovirulence, leading to outbreaks.

Understanding cVDPV2

The oral polio vaccine contains attenuated (weakened) strains of poliovirus that stimulate immunity without causing disease. However, in under-immunized populations, these strains can circulate, mutate, and, in rare instances, revert to a form capable of causing paralysis. This phenomenon results in cVDPV2 outbreaks, particularly in areas where vaccination rates are insufficient to prevent the spread of the virus.

cVDPV2 in Algeria

According to data from 2022, Algeria reported three cases of cVDPV2. citeturn0search10 By 2024, the number of reported cases had decreased to one, indicating progress in controlling the outbreak. citeturn0search10 This decline underscores the effectiveness of targeted immunization campaigns and heightened surveillance efforts.

Global Context

Algeria’s experience with cVDPV2 is part of a broader global challenge. In 2024, several countries reported cVDPV2 cases, with Nigeria (98 cases), Ethiopia (42 cases), and Yemen (37 cases) among the most affected. citeturn0search10 These statistics highlight the critical importance of maintaining high vaccination coverage worldwide to prevent such outbreaks.

Preventive Measures and Response

To combat cVDPV2, Algeria has implemented several key strategies:

• Enhanced Immunization Campaigns: Focusing on increasing OPV coverage, especially in regions with previously low vaccination rates.
• Surveillance Systems: Strengthening the monitoring of acute flaccid paralysis (AFP) cases to ensure rapid detection and response to potential polio cases.
• Public Awareness: Educating communities about the importance of polio vaccination to achieve and sustain herd immunity.

Conclusion

Algeria’s proactive measures against cVDPV2 have led to a notable reduction in cases, reflecting the country’s commitment to public health and polio eradication. Sustained efforts in immunization, surveillance, and public education are essential to prevent future outbreaks and to protect communities from the threat of vaccine-derived polioviruses.