Bangladeshi scientists find that new oral polio vaccine develops antibodies in infants

By SM Najmus Sakib

DHAKA, Bangladesh (AA) - A new study has found a World Health Organization (WHO) authorized oral vaccine for the type 2 poliovirus to be safe which develops 99% protective neutralizing antibodies in previously unvaccinated newborns.

Scientists at the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), an international health research organization based in Dhaka, and partners conducted the study, which was published in the peer-reviewed journal The Lancet, ICDDR,B said in a statement Sunday.

Dr. Md. K Zaman, a senior scientist in the Infectious Diseases Division at ICDDR,B, who led the study, told Anadolu Agency that “this is the first study…conducted on mothers in their third trimester of pregnancy and their infants and shows for the first time that the oral vaccine is safe and develops 99% antibodies.”

The WHO in November 2021 approved the new two-dose oral polio vaccine.

Dr. Zaman said “the novel oral polio vaccine is safe and immunogenic in the age group that most needs to be vaccinated to stop the chain of polio transmission in at-risk communities.”

Over 450 million doses of the newly authorized vaccine have been given under the WHO Emergency Use Listing Procedure, with no age restrictions for recipients, added Zaman, who is a former associate in the Department of International Health at US-based Johns Hopkins University.

There are three individual and immunologically distinct wild poliovirus strains. Concerns about possible outbreaks of circulating vaccine-derived poliovirus type 2 (cVDPV2) led the Global Polio Eradication Initiative to withdraw type 2 poliovirus from oral poliovirus vaccines (OPVs) and target only types 1 and 3.

“It will play a crucial role in controlling the polio virus muted after being vaccinated, or vaccine-derived poliovirus type 2 (cVDPV2),” said Zaman.

Under the study, a phase 2 trial was conducted in rural Bangladesh, at ICDDR,B’s Matlab Health Research Centre in Chandpur from Sept. 21, 2020 to Aug. 16, 2021. Overall, 327 women received two doses of the vaccine or placebos and among these, 325 were tested for immunogenicity per protocol, according to ICDDR,B.

Later, the WHO authorized the use of the new OPV against type 2 poliovirus called nOPV2, which is less likely to revert to neurovirulence.

“Thus, the findings of this new study will equip public health experts and policymakers with the evidence to inform use of nOPV2 in newborns with no previous exposure to other polio vaccines, who constitute the most vulnerable group for polio transmission,” said the study’s findings.

The study was carried out in collaboration with the Bill & Melinda Gates Foundation, the US Centers for Disease Control and Prevention (CDC), the International Vaccine Institute in Seoul and several other institutions and funded by the Bill & Melinda Gates Foundation.

The number of worldwide polio cases fell from an estimated 350,000 in 1988 to six in 2021 -- a decline of more than 99% in reported cases, according to the CDC.