Seven children were paralyzed by vaccine-derived polio linked to the new nOPV2 polio vaccine developed by the Bill & Melinda Gates Foundation, according to health officials in the Democratic Republic of the Congo and Burundi and the Global Polio Eradication Initiative (GPEI), which on Thursday announced the news.
Burundi declared a national emergency after confirming eight cases of the virus and five samples from environmental surveillance of wastewater, the World Health Organization (WHO) said in a statement.
The country plans to implement a polio vaccination campaign in the coming weeks, aiming to vaccinate all eligible children, ages 0 to 7, against the virus.
Burundi health authorities also plan to work with the WHO and GPEI to do risk assessments to determine the extent of the outbreak of the vaccine-derived virus.
And they are increasing polio surveillance, with WHO employees collecting additional water samples and possibly opening new environmental surveillance sites.
“We are disappointed,” said Dr. Ananda Bandyopadhyay, deputy director for technology, research and analytics on the Gates Foundation polio team. “Any such outbreak is disappointing,” he said, according to a Stat News report.
Vaccine-derived polio outbreaks are not a surprise with the nOPV2 vaccine, GPEI said. “While detection of these outbreaks is a tragedy for the families and communities affected, it is not unexpected with wider use of the vaccine,” it said on its website.
The oral vaccines, 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.
Children vaccinated with the live oral vaccines shed the virus in their stool, which eventually ends up in sewage wastewater. Particularly in places where sanitation is poor, the virus can move from child to child, which, GPEI said, is actually the point.
The viruses can move from person to person and “actually help protect the community” it says on its website.
However, as it continues to circulate over the course of 12 to 18 months, the attenuated virus in the live oral vaccine strains can revert to virulence, circulate, infect and paralyze “in places with low immunization rates.”
These viruses are called circulating vaccine-derived poliovirus, or cVDPV.
Afghanistan and Pakistan now report more cases of paralysis from vaccine-derived polio than from the wild virus, and there have been several outbreaks of vaccine-derived infections across Africa, with more than 1,000 children paralyzed in 2020 alone, according to a study in the BMJ.
In 2022, 800 children developed paralytic polio from the vaccines.
Why live virus vaccines?
The oral polio vaccines (OPV) used in much of the developing world are different from those given in the U.S. and some western countries, which use the inactivated (dead) polio vaccine (IPV) developed by Dr. Jonas Salk and first used in 1955, when polio became a global concern.
According to the WHO, it’s only in “very rare cases,” that the administration of OPV results in vaccine-derived paralytic polio.
In addition to causing vaccine-associated paralytic polio, vaccine strains have the capacity to cause disease of the nervous system and to transmit from person to person, resulting in infectious poliomyelitis, The Defender reported.
The U.S. stopped using OPV in 2000 because it caused paralytic polio….