The GPEI added that the isolated viral samples stem from two separate and new cVDPV2 outbreaks linked to nOPV2. These outbreaks reportedly began in the DRC’s Tangyanika and South Kivu provinces. Meanwhile, the World Health Organization (WHO) said Burundi had already declared a national emergency following eight cases and five wastewater samples testing positive for cVDPV2.
The oral polio vaccines (OPVs) – administered in much of Africa, the Middle East and parts of Asia – contain a live-but-weakened form of the polio virus modified to minimize its ability to paralyze. However, the attenuated virus in the live oral vaccine strains can revert to virulence, circulate, infect and paralyze “in places with low immunization rates” over the course o 12 to 18 months.
“Vaccine of choice” for polio ironically spreading the disease
The Bill & Melinda Gates Foundation (BMGF), one of GPEI’s partners, funded the development and clinical trials for nOPV2. “We are disappointed. Any such outbreak is disappointing,” lamented Dr. Ananda Bandyopadhyay, deputy director for technology, research and analytics on the BMGF’s polio team.
According to the Defender, GPEI and BMGF rushed to develop new OPVs that would make the virus less prone to mutations – which are responsible for the health problems it causes. The WHO granted nOPV2 an emergency use listing in November 2020, and the global health body’s Strategic Advisory Group of Experts on Immunization recommended the BMGF-funded nOPV2 to become the “vaccine of choice” for responding to type 2 vaccine-derived polio outbreaks. However, nOPV2 is now associated with vaccine-related polio outbreaks. (Related: UKHSA: Vaccine-derived poliovirus found in London sewage samples.)
Children’s Health Defense (CHD) Chief Scientific Officer Dr. Brian Hooker lamented the cVDPV2 outbreaks in the DRC and Burundi.
“It is tragic, but not unexpected that the use of live virus vaccines would cause the spread of vaccine-derived polio – given the propensity of these viruses to back-mutate into their paralytic form,” he wrote in an email. “It is even more alarming that the paralytic form is now circulating among the population of the [DRC’s] and Burundi’s children.”
Meanwhile, GPEI said 600 million doses of the new vaccine were administered in 28 countries since March 2021. While it reiterated that nOPV2 was “safe and effective,” data would otherwise debunk this claim. According to CHD, 800 children developed paralytic polio from the oral vaccines in 2022.
No comments:
Post a Comment