December 29, 2021
3 min read
Source/Disclosures
Published by:
Disclosures:
The authors report no relevant financial disclosures.
A new report highlighted the COVID-19 pandemic’s ongoing impact on efforts to eradicate polio.
According to the report, published recently in MMWR, 37 countries reported 44 outbreaks of circulating vaccine-derived poliovirus from January 2020 through June 2021 — almost 90% of them caused by poliovirus type 2. The outbreaks resulted in 1,335 paralyzed children.
Source: Adobe Stock.
In 2016, more than 150 countries transitioned from using a trivalent oral polio vaccine to using a bivalent vaccine containing only types 1 and 3 following the eradication of the wild type 2 strain. Since the switch, a monovalent type 2 poliovirus vaccine has been used to respond to vaccine-derived polio outbreaks.
In November 2020, WHO issued an emergency use listing for a novel type 2 oral poliovirus vaccine that was developed to be more genetically stable than the other vaccine, but supply has been limited “because of manufacturing delays resulting from the COVID-19 pandemic and larger than anticipated [vaccine] consumption,” Mary M. Alleman, PhD, an epidemiologist for the CDC’s Global Immunization Division, wrote.
We spoke with Alleman about disruptions caused by the pandemic, which the authors said may have resulted in an undercounting of polio cases and delayed the detection of outbreaks.
Healio: Is COVID-19 still impacting eradication activities?
Alleman: The COVID-19 pandemic has compromised health systems and limited access to vital treatments and public health interventions, such as surveillance for vaccine preventable diseases and administration of vaccines.
The 4-month suspension of polio vaccination campaigns in early 2020 in more than 30 countries to protectcommunities and staff from COVID-19, coupled with related disruptions to routine immunization, led to tens of millions of children missing polio vaccination and has contributed to the spread of circulating vaccine-derived poliovirus type 2 (cVDPV2s), mainly in the WHO African Region. The pandemic has also diverted resources and personnel from poliovirus surveillance.
Despite setbacks, the Global Polio Eradication Initiative (GPEI) has been working alongside all countries with active wild or circulating vaccine-derived poliovirus outbreaks to resume polio immunization activities and recover lost ground. GPEI has adapted to the challenges of operating during the COVID-19 pandemic by updating surveillance strategies, developing informational dashboards and innovating approaches to ensure the prompt arrival pf stool specimens and environmental samples to laboratories in the Global Polio Laboratory Network. GPEI supports poliovirus surveillance to detect and monitor the evolution of poliovirus outbreaks around the world and supports timely vaccination responses to stop outbreaks. After the early 2020 suspension, the implementation of polio campaigns gradually resumed beginning in the third quarter of 2020 on a country-by-country basis.
Healio: Has the global eradication goal been set back further?
Alleman: In May, the GPEI launched an updated 5-year strategy through 2026, transforming its approach to overcome remaining hurdles, including setbacks from the COVID-19 pandemic, to help strengthen immunization systems in affected countries and deliver and maintain a polio-free world.
The strategy focuses onadopting an emergency posturewhile generating greater accountability and ownership from country governmentstocertify the eradication ofwild poliovirus type 1by 2026 and to interrupt cVDPV2 transmission by the end of 2023.
Healio: Is there a shortage of vaccine?
Alleman: Because of high levels of demand for the novel oral poliovirus type 2 vaccine (nOPV2), as well as the negative impacts of COVID-19 on its production, supply of the novel vaccine will be limited in the near term. Distribution will be guided by a GPEI prioritization framework while GPEI works to increase supply.
Because of the public health emergency posed by cVDPV2 outbreaks, it is critical that countries prioritize immediate and high-quality outbreak responses. The recommendation from the Strategic Advisory Group of Experts on Immunization, the WHO Director-General’s Emergency Committee for the International Health Regulations regarding the spread of poliovirus as a Public Health Emergency of International Concern, and the GPEI Independent Monitoring Board is that countries should initiate rapid outbreak response with available type 2 OPV, whether that is Sabin (mOPV2) or the novel vaccine.
In situations where there is co-circulation of poliovirus serotypes, or where there are cVDPV1/cVDPV3 outbreaks, trivalent oral polio vaccine (tOPV) or bivalent oral polio vaccine (bOPV) may be the more appropriate vaccine choice.
There is not a shortage of mOPV2, bOPV or tOPV.
COVID-19 Resource Center
