Oral Polio Vaccine to Mitigate the Risk of Illness and Mortality During the Coronavirus Disease 2019 Pandemic: A Cluster-Randomized Trial in Guinea-Bissau

Abstract

Background Oral Polio Vaccine (OPV) may improve resistance to non-polio-infections. We tested if OPV reduced the risk of illness and mortality prior to COVID-19-vaccines being available. Methods During the early COVID-19 pandemic, houses in urban Guinea-Bissau were randomised 1:1 to intervention or control. Residents aged 50 + years were invited to participate. Participants received bivalent OPV (single dose) or nothing. Rates of mortality, admissions, and consultation for infections (primary composite outcome) during 6 months of follow-up were compared in Cox proportional hazards models adjusted for age and residential area. Secondary outcomes included mortality, admissions, consultations, and symptoms of infection. Results We followed 3726 participants (OPV: 1580; Control: 2146) and registered 66 deaths, 97 admissions and 298 consultations for infections. OPV did not reduce the risk of the composite outcome overall, hazard ratio (HR) = 0.97 (95%CI: 0.79-1.18). OPV reduced the risk in males (HR = 0.71 (0.51-0.98) but not in females (HR = 1.18 (0.91-1.52), p for same effect = 0.02). OPV also reduced the risk in BCG scar-positive (HR = 0.70 (0.49-0.99) but not in scar-negative participants (HR = 1.13 (0.89-1.45), p = 0.03). OPV had no overall significant effect on mortality (HR = 0.96 (0.59-1.55)), admissions (HR = 0.76 (0.49-1.17)) or recorded consultations (HR = 0.99 (0.79-1.25)), but the OPV group reported more episodes with symptoms of infection (6050 episodes; HR = 1.10 (1.03-1.17)). Conclusion In line with previous studies, OPV had beneficial non-specific effects in males. Trial Registration www.clinicaltrials.gov/NCT04445428

Inactivated Poliovirus Vaccine Booster Reduces the Likelihood of COVID-19 Outcomes in Individuals Primed with Oral Poliovirus Vaccination

“…The findings also validate prior studies that suggest poliovirus vaccination may be associated with lower risks of SARS-CoV-2 infection and COVID-19 mortality [ 45 , 51 , 52 , 53 , 59 ]. While most studies have focused on OPV, participants enrolled in the clinical trial analyzed herein were inoculated with IPV.…”

“…Overall, 282 participants (age, median [range], 55 [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , …”

“…Interestingly, countries that use OPV for their childhood vaccination campaigns have reported lower incidence rates of SARS-CoV-2 infection compared with those that solely use IPV [ 50 ]. Accordingly, nearly all studies examining the effects of poliovirus vaccination on COVID-19 morbidity and mortality have focused on OPV [ 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 ]. To date, the only published study examining the effects of IPV on SARS-CoV-2 RdRp is an in vitro retrospective analysis of polio-immune serum samples.…”

The impact of trained immunity in respiratory viral infections

“…42 In Guinea-Bissau, the OPV also reduced the risk of illness and mortality due to SARS-CoV-2 infection only in male adults of more than 50 years of age. 43 A study in Iran showed that passive exposure of women through children who received the live-attenuated polio vaccine was associated with reduced symptomatic infection with SARS-CoV-2. 44 A recombinant zoster vaccine adjuvanted with AS01 was shown to decrease the risk of SARS-CoV-2 infection and hospitalisation in older adults by 16% and 32%, respectively.…”

Oral polio revaccination is associated with changes in gut and upper respiratory microbiomes of infants

“…The development of a heterologous adaptive host immune response and the so-called, trained immunity or innate immune memory, i.e., epigenetic and metabolic reprogramming of innate immune cells ( Netea et al, 2016 ), have been pointed out as possible immune mechanisms behind NSE. BCG’s capacity to induce a heterologous adaptive immune response and trained immunity has been confirmed in clinical trials with healthy adult volunteers ( Kleinnijenhuis et al, 2012 , 2014 ), and a recent retrospective analysis done at Mayo Clinic raised a possible role for trained immunity toward the partial protection provided by OPV against SARS-CoV-2 infection ( Pawlowski et al, 2021 ) and some authors even found that OPV immunization vs. placebo reduced the number of laboratory-confirmed COVID-19 infections ( Yagovkina et al, 2022 ) and improved overall health in males during the COVID-19 pandemic ( Fisker et al, 2022 ). Eradication of polio infection preconizes the withdrawal of OPV from routine immunization programs ( World Health Organization [WHO], 2021b ).…”