Intestinal Antibody Responses to 2 Novel Live Attenuated Type 2 Oral Poliovirus Vaccines in Healthy Adults in Belgium

Abstract

In a blinded phase 1 trial (EudraCT 2017-0000908-21; NCT03430349) in Belgium, healthy adults (aged 18-50 years) previously immunized exclusively with inactivated poliovirus vaccine were administered a single dose of 1 of 2 novel type 2 oral poliovirus vaccines (nOPV2-c1: S2/cre5/S15domV/rec1/hifi3 (n = 15); nOPV2-c2: S2/S15domV/CpG40 (n = 15)) and isolated for 28 days in a purpose-built containment facility. Using stool samples collected near days 0, 14, 21, and 28, we evaluated intestinal neutralization and immunoglobulin A responses to the nOPV2s and found that nOPV2-c1 and nOPV2-c2 induced detectable poliovirus type 2-specific intestinal neutralizing responses in 40.0% and 46.7% of participants, respectively.

Keywords: eradication; intestinal antibodies; live attenuated vaccine; mucosal immunity; poliovirus.

Figure 1.

Reverse cumulative distribution functions of poliovirus type 2–specific stool neutralizing activity and immunoglobulin A (IgA) levels before and after receiving nOPV2-c1 (n = 15) (A, B) or nOPV2-c2 (n = 15) (C, D). Because stool samples were not available for all participants on all days, we described the aggregate of the measurements obtained from samples collected on days −2 to 0 (before vaccination) for day 0, days 12–16 for day 14, days 19–23 for day 21, and days 26–30 for day 28. If ≥2 stool samples were collected within each window for a given participant, we calculated the geometric mean of the stool neutralization titer or IgA mean fluorescence intensity (MFI).