The World Health Organisation (WHO) has officially granted prequalification status to the novel type 2 oral polio vaccine (nOPV2), achieving a significant milestone three years after being granted Emergency Use Listing (EUL).
Developed with contributions from scientists at the UK Medicines and Healthcare Products Regulatory Agency (MHRA), the nOPV2 has undergone rigorous testing and demonstrated effectiveness in immunized populations. The WHO’s decision follows the distribution of 950 million doses globally, reaffirming the safety and efficacy of the vaccine.
Importance of nOPV2:
- The nOPV2 is a modified version of the oral polio vaccine (OPV), designed to specifically target poliovirus type 2.
- This modification aims to reduce the risk of vaccine-derived outbreaks, a concern arising when the weakened virus in the vaccine circulates in under-immunized populations, potentially regaining the ability to cause paralysis.
- Key genetic modifications, including a stabilized RNA stem-loop structure, underwent thorough pre-clinical testing before clinical development, ensuring the vaccine’s effectiveness against polio while minimizing the potential for the virus to mutate.
The WHO’s prequalification of nOPV2 streamlines access for member countries, eliminating the stringent criteria mandated under the EUL. This status ensures broader availability for global organizations to supply and distribute the nOPV2 in developing nations.
Key Points to Note:
- Polio, primarily transmitted through contaminated food and water, poses a significant threat to infants and young children, potentially resulting in severe paralysis or fatality.
- Oral polio vaccines, including the nOPV2, have played a crucial role in reducing global polio cases, with their characteristic of not requiring stringent cold storage facilitating immunization efforts in remote areas.
- Three years ago, amid concerns about vaccine-derived outbreaks in Asia and Africa, the nOPV2 became the first vaccine to gain WHO EUL, paving the way for its current pre-qualification.
- The global polio eradication initiative and International Health Regulations (IHR) classify Nigeria as a state infected with circulating vaccine-derived poliovirus type 2, with 62 outbreaks reported in 2022.
- This decision represents a pivotal step forward in strengthening global immunity against polio, underscoring the collective commitment to ensuring that children worldwide receive safer and more accessible polio vaccines.
