Immunogenicity and safety of a booster dose of inactivated polio vaccine / 中华预防医学杂志

<p><b>OBJECTIVE</b>To evaluate the immunogenicity and safety of a boost dose of inactivated polio vaccine (IPV) among children aged 18 months who had been administered with primary doses of IPV.</p><p><b>METHODS</b>Form 2011 to 2012, a total of 97 children were enrolled in the present study who were vaccinated with IPV at 2, 3, 4 months of age and boosted with the same vaccine at 18 months of age. Anti-poliovirus neutralizing antibody titers in serum were measured before and after booster vaccination, geometric mean titers (GMT) and seroprotection rate were calculated. Adverse events occurring within 30 days after booster vaccination were observed, including pain, redness/swelling and induration at the injection site, fever, vomit, abnormal crying, drowsiness, loss of appetite, irritability, and all other physical discomfort and related medications were also recorded. A descriptive analysis was performed for the safety assessment.</p><p><b>RESULTS</b>Immunogenicity was assessed in 84 subjects. The pre-booster seropositivity rates of neutralizing antibody against poliovirus type 1, 2, 3 before booster were all 100% (84/84) and the corresponding GMT (95% CI) was 1: 148.5 (116.49-189.29) , 1: 237.68 (178.39-316.67) and 1: 231.87 (181.27-296.58) , respectively. The seropositivity rates of neutralizing antibody against the three types of poliovirus after booster were all 100% (84/84) and the corresponding GMT (95% CI) was 1: 1612.14 (1470.57-1767.34) , 1: 1854.92 (1715.83-2005.29) and 1: 1625.50 (1452.12-1819.58) , respectively. The pre-booster titer of neutralizing antibody against poliovirus type 1, 2, 3 mainly ranged 1: 128-1: 512, which accounted for 65% (55/84) , 55% (46/84) , 74% (62/84) in each type. After the booster immunization, titers of neutralizing antibody against type 1, 2, 3 were increased as subjects with titer ≥ 1: 1024 accounted for 94% (78/84) , 95% (80/84) , 92% (77/84) , respectively.Safety was evaluated in 96 subjects, of which 16 subjects reported adverse events with the rate of 17%. The observed local events were mainly tenderness 3% (3/96) , redness/swelling and induration were not reported. The systemic adverse events included loss of appetite (8%, 8/96) , irritability (8%, 8/96) , fever (7%, 7/96) , abnormal crying (6%, 6/96) , drowsiness (6%, 6/96) and vomit (1%, 1/96) . All reported adverse events were mild or moderate. All of the local events occurred in the day of vaccination and lasted for 1-2 days, while systemic events almost developed within 2 days after vaccination and last less than 3 days.</p><p><b>CONCLUSION</b>IPV booster dose has good immunogenicity and safety profile, which provides effective protection against poliovirus.</p>

Safety of different sequential immunization schedules of inactivated poliovirus vaccine and oral poliovirus vaccine primary vaccination / 中华预防医学杂志

<p><b>OBJECTIVE</b>To evaluate safety of different sequential immunization schedules of inactivated poliovirus vaccine (IPV) and oral poliovirus vaccine (OPV) primary vaccination.</p><p><b>METHODS</b>Infants of 2 months old (60-89 days) selected in Beijing, were assigned to four groups, 1 dose IPV plus 2 doses OPV (I-O-O), 2 doses IPV plus 1 dose OPV(I-I-O), 3 doses IPV (I-I-I), and 3 doses OPV (O-O-O), and were vaccinated at the age of 2, 3, 4 months, from 2009 to 2011. The frequencies of systemic as well as local injection site reactions after every dose were recorded and calculated. A total of 553 infants were enrolled in the study and 89 infants were quit, 1492 diseases were observed.</p><p><b>RESULTS</b>The incidence of adverse events in I-O-O, I-I-O, I-I-I, O-O-O were 22.9% (94/410), 18.4% (60/327), 22.0% (78/354) and 17.7% (71/401) with no statistical differences (χ(2) = 4.84, P = 0.184). Dose 1 (22.7% (32/141)-35.3% (54/153) ) was more frequently than dose 2 and dose 3. No serious adverse events (SAE) were reported during the study. The incidence of systemic adverse reactions in I-O-O, I-I-O, I-I-I, O-O-O were 21.5% (88/410), 17.7% (58/327) , 20.1% (71/354) and 17.7% (71/401) with no statistical differences (χ(2) = 2.53, P = 0.472). Abnormal crying were the most frequency reactions (7.2% (29/401)-11.3% (37/327) ) in 4 groups. Rarely severe reactions were observed of abnormal crying, somnolence, irritability and mild or medium reactions occurred in other symptoms. Local adverse reactions such as injection site pain, scleroma and swelling were reported by 2.2% (5/229)-5.6% (22/393) ,0-0.9% (2/229) and 0-1.0% (4/393) in I-O-O,I-I-O and I-I-I, and most reactions were mild.</p><p><b>CONCLUSION</b>Three IPV immunization and IPV/OPV sequential immunization as well as three OPV immunization demonstrated safe.</p>

Study of immunogenicity after primary vaccination by different sequential program of inactivated poliovirus vaccine and oral poliovirus vaccine / 中华预防医学杂志

<p><b>OBJECTIVE</b>To evaluate immunogenicity after primary vaccination by different sequential program of inactivated poliovirus vaccine (IPV) and oral poliovirus vaccine (OPV).</p><p><b>METHODS</b>Children of 2 months old (60-89 days) selected in Beijing were assigned to 4 groups, 1 dose IPV plus 2 doses OPV (I-O-O, 122 children), 2 doses IPV plus 1 dose OPV(I-I-O, 103 children), 3 doses IPV (I-I-I, 114 children), and 3 doses OPV (O-O-O, 106 children), and were vaccinated at the age of 2, 3, 4 months. Polio neutralizing antibody titers against poliovirus types 1, 2, and 3 were tested and protective rates were calculated before the 1st dose, after the last dose, and after the 1st and 2nd dose of IPV.</p><p><b>RESULTS</b>After the primary immunization, geometric mean titers (GMT) of polio neutralizing antibody titers against poliovirus types 1, 2, and 3 were 788.32, 738.42 and 631.17 in O-O-O group, 212.02, 262.30 and 537.52 in I-I-I group, 940.35, 929.72 and 940.35 in I-O-O group and 901.09, 1102.68 and 1110.12 in I-I-O group (F values were 47.71, 53.84, and 9.81 respectively, all P values<0.01). The protective rate of three types among each group was 98.1% (104/106)-100.0% and the difference was not statistically significant (P>0.05). After the 1(st) dose of IPV, the GMT were 18.88, 37.77, 24.64 and the protective rate was 82.6% (122/138)-96.4% (133/138); after the 2nd dose of IPV, GMT were 177.03, 168.25, 321.86 and the protective rate was 99.1% (108/109)-100.0% (109/109) in antibody types 1, 2 and 3, respectively.</p><p><b>CONCLUSION</b>GMT of polio neutralizing antibody titers against poliovirus is higher after vaccination by sequential program of IPV and OPV than that by IPV or OPV 3-doses program. High level of protective rate after 2 doses of IPV in I-I-O group may lead to better protection from vaccine associated paralytic poliomyelitis (VAPP). Sequential program of IPV and OPV can be used to maintain high level of herd immunity and to prevent VAPP, and the I-I-O sequential program should be the first choice.</p>