Advances in Polio Vaccines: New Strategies to Combat Vaccine-Derived Polio Outbreaks

New Polio Vaccines Developed to Combat Vaccine-Derived Polio Outbreaks

In 1980, the eradication of smallpox raised hopes that the polio virus would be next. While progress has been made in eradicating polio, cases of vaccine-derived polio are on the rise. Last year, 665 cases of polio of vaccine origin were registered in 23 countries. Vaccine-derived polio occurs when the attenuated poliovirus used in oral vaccines regains its virulence.

In a recent edition of the magazine Nature, Andrew Macadam and colleagues at the National Institute for Biological Standards and Control in the UK reported on the development of new polio vaccines. These oral medications aim to reduce the likelihood of outbreaks of types 1 and 3 poliovirus. The vaccines were created using a method previously used to make a new type 2 polio vaccine known as nOPV2.

The scientists used genetic engineering to significantly reduce the chances of the attenuated virus regaining its virulence. The two new vaccines were tested in mice and found to be effective, safe, and stable. They are currently undergoing human trials. If their safety and efficacy are as good as those of the nOPV2 vaccine, all three poliovirus subtypes will be covered.

Since March 2021, the nOPV2 vaccine has been administered to over 650 million children in 30 countries. However, while nOPV2 is more genetically stable than its predecessor, it can still regain virulence. This has occurred on four separate occasions in Nigeria and the Democratic Republic of the Congo. This highlights the need for comprehensive health initiatives alongside scientific advances to eradicate polio.

The increase in cases of vaccine-derived polio can be attributed to several factors. The COVID-19 pandemic has complicated vaccination campaigns and supervision. Disasters and conflicts in vulnerable countries have also hindered efforts. Additionally, some countries have delayed their outbreak responses, waiting for supplies of the nOPV2 vaccine instead of using the older type 2 vaccine.

Changes in the management of polio campaigns have also contributed to the deterioration of some campaigns. The Global Polio Eradication Initiative (GPEI),

How have factors such as the COVID-19 pandemic, conflicts in vulnerable countries, and changes in polio campaign management contributed to the increase in vaccine-derived polio cases

In the pursuit of eradicating polio, researchers have developed new vaccines to combat the increasing cases of vaccine-derived polio. While progress has been made in reducing polio cases, instances of vaccine-derived polio have been on the rise. In 2020 alone, 665 cases of polio originating from vaccines were reported across 23 countries. Vaccine-derived polio occurs when the weakened poliovirus used in oral vaccines regains its virulence.

A team of scientists led by Andrew Macadam at the National Institute for Biological Standards and Control in the UK has recently published a study in the journal Nature, detailing the development of two new polio vaccines. These oral vaccines specifically target types 1 and 3 poliovirus, aiming to minimize the likelihood of outbreaks. The researchers utilized a genetic engineering technique that greatly reduces the chances of the weakened virus regaining its virulence. Preliminary tests conducted on mice demonstrated the vaccines’ efficacy, safety, and stability. Currently, these vaccines are undergoing human trials. If proven to be as effective and safe as the previously developed nOPV2 vaccine, all three subtypes of poliovirus will be covered by these vaccines.

Since March 2021, the nOPV2 vaccine has been administered to over 650 million children in 30 countries. While the nOPV2 vaccine is more genetically stable than its predecessor, there have been instances where it has regained virulence. This has been observed in Nigeria and the Democratic Republic of the Congo on four separate occasions. These cases underscore the importance of comprehensive health initiatives in conjunction with scientific advancements to achieve the eradication of polio.

There are several factors contributing to the increase in vaccine-derived polio cases. The COVID-19 pandemic has posed challenges to vaccination campaigns and surveillance efforts. Additionally, disasters and conflicts in vulnerable countries have hindered eradication efforts. Furthermore, certain countries have delayed their outbreak responses, waiting for supplies of the nOPV2 vaccine instead of utilizing the older type 2 vaccine.

Changes in the management of polio campaigns have also played a role in the decline of some initiatives. The Global Polio Eradication Initiative (GPEI) has recognized the need for revised strategies and plans to address the setbacks and ensure progress in the fight against polio. It is crucial to implement comprehensive and coordinated efforts that combine effective vaccines, robust surveillance, and efficient vaccination campaigns to achieve the ultimate goal of global polio eradication.