The impact of immunization with bivalent oral poliovirus vaccine on the incidence of COVID-19

In a latest research printed in Frontiers in Immunology, researchers evaluated the affect of the oral poliovirus vaccine (OPV) on the incidence of coronavirus illness 2019 (COVID-19).

Study: Vaccination With Oral Polio Vaccine Reduces COVID-19 Incidence. Image Credit: frank60/Shutterstock
Examine: Vaccination With Oral Polio Vaccine Reduces COVID-19 Incidence. Picture Credit score: frank60/Shutterstock


Fast interventions throughout an emergent pandemic are essential to curbing the transmission of causal pathogens till vaccination is launched. In mild of the COVID-19 pandemic, a number of measures have been carried out to restrict the unfold of extreme acute respiratory syndrome coronavirus 2 (SARS-CoV-2). These included bodily distancing, masking, journey restrictions, nationwide or regional lockdowns, and so on. Though efficient, these measures are momentary and disrupt financial and social actions; thus, reaching inhabitants immunity should be the perfect answer.

On this regard, vaccines towards SARS-CoV-2 have been developed in report time, given the exigency, and several other vaccines have been approved for emergency use. Nonetheless, many challenges regarding world rollout emerged, notably in low-income international locations with poorly developed well being infrastructure. The emergence of mutant variants of SARS-CoV-2, which exhibited substantial resistance to vaccine-induced immune responses, was one other obstacle.

Prior analysis means that live-attenuated vaccines (LAVs) induce broad safety towards off-targets. This was noticed for OPV, measles vaccine, and Bacillus Calmette-Guerin (BCG) vaccine, amongst others. One research confirmed that OPV diminished the incidence of influenza within the Soviet Union within the late Sixties. As such, it has been speculated that LAVs would possibly confer a broad protecting impact towards SARS-CoV-2.

Concerning the research

Within the current research, researchers assessed the impact of vaccination with OPV on COVID-19 incidence. The research was performed on the Kirov Medical College from Could 14, 2020, to January 11, 2021. Members aged 18 to 65 have been eligible, supplied they have been wholesome with none continual circumstances or abnormalities. Excluded contributors have been these with a historical past of COVID-19 an infection, immunodeficiency, immunosuppression, malignant neoplasms, vaccine hypersensitivity, or different problems.

Eligible topics have been equally randomized to check/vaccine and placebo cohorts. Members within the research cohort acquired a 0.2 ml dose of bivalent OPV 1 and three, whereas placebo contributors acquired sterilized distilled water. Blood samples have been obtained from 20 placebo contributors and 40 vaccinated contributors on every go to.

Neutralizing antibodies (nAbs) towards poliovirus have been decided utilizing a microneutralization assay. The first research final result was estimating the variety of COVID-19 instances in every group inside three months of OPV or placebo administration. COVID-19 instances have been confirmed by polymerase chain response (PCR) or serological assessments. Secondary outcomes of the research have been the whole variety of acute respiratory infections (ARIs), similar to frequent chilly, influenza, and so on., in every cohort, the severity and length of sickness, and deaths.


Total, 558 and 557 contributors have been enrolled within the research and placebo cohorts. The questionnaire captured information on earlier ARI historical past, revealing that contributors in every cohort have been typically sick twice or annually. No participant was vaccinated towards SARS-CoV-2 earlier than or throughout the research interval. All contributors have been beforehand vaccinated towards poliomyelitis. Sera samples obtained on visits 1 and a pair of exhibited neutralizing exercise towards attenuated Sabin polioviruses.

At first of the research, antibodies have been detected in all topics towards at the least two serotypes of poliovirus. Nonetheless, eight topics (two from placebo and 6 from research cohorts) had no detectable nAb titers towards sort 3 poliovirus, suggesting waning safety towards this serotype. On the second go to, i.e., after a month of vaccine/placebo administration, placebo contributors confirmed no improve in nAb titers.

Alternatively, people from the research cohort confirmed a 16-fold improve in nAb titers towards sort 3 poliovirus and 5.6-fold towards sort 1 poliovirus. About 25 people from the research cohort have been recognized with COVID-19 in comparison with 44 COVID-19 instances within the placebo group, which was statistically vital. This meant that COVID-19 incidence was 1.8-times decrease in OPV-vaccinated topics than in placebo recipients. Deaths weren’t recorded in both cohort.

4 COVID-19 instances have been documented inside a month of OPV administration in comparison with seven instances within the placebo cohort, albeit this distinction was statistically insignificant given the less instances. Additional, placebo recipients exhibited a 1.9-fold increased relative threat of contracting SARS-CoV-2 than OPV-vaccinated topics throughout the first month.

ARI occasions have been (self)-reported by 68 OPV-vaccinated topics and 66 placebo recipients. ARI incidence was decrease in vaccinated topics than in placebo recipients; nevertheless, it was not statistically vital.


The findings revealed that COVID-19 incidence was decrease amongst topics vaccinated with OPV than those that acquired a placebo. Furthermore, OPV-vaccinated people had a decrease threat of contracting COVID-19 an infection than placebo contributors.

Notably, the frequency of SARS-CoV-2-positive PCR or serological assessments amongst contacts of individuals with ARI or COVID-19 was increased within the placebo cohort than in vaccinated topics. This recommended that OPV would possibly confer resistance to SARS-CoV-2 an infection. Nonetheless, extra analysis is required to characterize the protecting results of vaccination with OPV or LAVs towards SARS-CoV-2.  

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