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>

The epidemiological impact of varicella vaccination in kindergartens, primary and secondary schools in Beijing / 中华预防医学杂志

<p><b>OBJECTIVE</b>To study the epidemiological impact of varicella vaccine vaccination on kindergartens and school children in Beijing.</p><p><b>METHODS</b>According to "China Information System for Diseases Control and Prevention", the reported clinical diagnosis varicella cases were tracked in kindergartens, primary and secondary schools whose onset date were from 2008 to 2010. Epidemiological survey was conducted and epidemiological features were analyzed.</p><p><b>RESULTS</b>A total of 21 474 varicella cases were investigated: 55.3% (11 883 cases) had been vaccinated by varicella vaccine. Of cases with definite immunization history, interval between vaccination date and onset date were from 30 days to 1 year accounted for 3.4% (286/8510), 1 to 3 years accounted for 18.2% (1551/8510), 3 to 5 years accounted for 28.6% (2431/8510), 5 to 10 years accounted for 34.3% (2916/8510) (left-closed right-open interval); The peak age of onset was 4 years old in cases without immunization history, which was 6 years old in cases with immunization history; The proportion of cases with immunization history (≥ 30 days) had increased from 42.4% (2862/6754) in 2008 to 56.3% (4327/7679) in 2010. The cases with no fever had a higher proportion (54.9%, 6413/11 679) of immunization history (≥ 30 days) than cases with fever (47.7%, 4533/9500) (P < 0.01); The cases with rashes less than 50 had a higher proportion (57.4%, 8045/14 020) of immunization history (≥ 30 days) than cases with rashes more than 50 (40.2%, 2902/7216) (P < 0.01).</p><p><b>CONCLUSION</b>Varicella vaccine delays the peak age of onset, alleviates the symptoms. The current immunization strategy can not block varicella spread in kindergartens, primary and secondary schools.</p>

Safety and epidemiological effects of the first China-made mass A (H1N1) influenza vaccination / 中华流行病学杂志

Objective To evaluate the safety and epidemiological effects on the first mass vaccination program, using the China-made A (H1N1) influenza vaccine. Methods Descriptive epidemiology and cohort study design were used to assess the influenza A H1N1 vaccine on its safety and epidemiological effects. Results 95 244 subjects were immunized with A (H1N1) influenza vaccine. 193 adverse events were reported through AEFI Management System, with the Reported rates after immunization was carried out. Of 81 adverse reactions confirmed to be related to immunization,reported through the AEFI Management System. The epidemiological protection rate of A (H1N1)influenza vaccine showed a similar safety profile to seasonal flu vaccine. The vaccine demonstrated a good epidemiological effects against A (H1N1) influenza virus infection.

Analysis of adverse events following 2009 influenza A (H1N1) vaccinoprophylaxis in Beijing / 中华预防医学杂志

<p><b>OBJECTIVE</b>To evaluate the safety of 2009 influenza A (H1N1) vaccine based on mass immunization initiative in Beijing.</p><p><b>METHOD</b>There were 2 113 280 people were vaccinated during September to December 2009. The information of adverse events following immunization (AEFI) was collected through surveillance system, and descriptive methodology was used for data analysis.</p><p><b>RESULTS</b>A Total of 612 AEFI cases were reported, among which there were 321 vaccine reaction cases following immunization, 203 coincidental illness cases, 82 psychogenic reaction cases, and 6 pending cases. The rates of rare reactions and common reactions associated with vaccination were respectively 5.54/100 000 (117/2 113 280) and 9.65/100 000 (204/2 113 280). The rate of serious rare reaction was 0.19/100 000 (4/2 113 280). The rates of vaccine reactions in urban, suburb and county were 16.87/100 000 (36/213 519), 17.81/100 000 (187/1 049 817) and 11.53/100 000 (98/849 944), respectively. The rates of rare reaction and common reaction in different age groups were between 3.65/100 000 (6/164 604) to 8.99/100 000 (27/300 176), and between 0.61/100 000 (1/164 604) to 22.06/100 000 (85/385 275). The 117 rear vaccine reaction cases were mainly allergic reaction (107 cases), and the 204 common vaccine reaction cases were mainly fever (176 cases). There were 91.90% (295/321) vaccine reactions occurred within 24 hours of administration, and all cases had improved consequence.</p><p><b>CONCLUSION</b>The mostly symptoms of AEFI cases during the period of 2009 influenza A (H1N1) vaccinoprophylaxis were anaphylaxis and fever. The types of adverse reactions and the level of serious events are consistent with the anticipation. There were no rear or new events occurred.</p>

Comparison between early outbreak detection models and simulated Outbreaks of measles in Beijing / 中华流行病学杂志

Objective Using simulated outbreaks to choose the optimal model and its related parameters on measles so as to provide technical support for developing an Auto Warning System(AWS).Methods AEGiS-Cluster Creation Tool was applied to simulate a range oftmique outbreak signals.Then these simulations were added to the aetnal daily counts of measles from the National Disease Surveillance System,between 2005 and 2007.Exponential weighted moving average(EWMA),C1-MILD(C1),C2.MEDIUM(C2).C3-ULTRA(C3)and space.time permutation scar statistic model were comprehensively applied to detect these simulations.Tools for evaluation as Youden's index and detection time were calculated to optimize parameters before an optimal model was finally chosen.Results EWMA(λ=0.6,κ=1.0),C1(κ=0.1,H=3σ),C2(k=0.1,H=30),C3(κ=1.0,H=4σ)and space-time permutation scan statistic(maximum temporal cluster size=7 d,maximum spatial cluster size=5 km)appeared to be the optimal parameters among these models.Youden's index of EWMA was 90.8%and detection time being 0.121 d.Youden's index of C1 was 88.7%and detection time being 0.142 d.Youden's index of C2 was 92.9%and detection time being 0.121 d.Youden's index of C3 was 87.9%and detection time being 0.058 d.Youden's index of space-time permutation scan statistic was 94.3%and detection time being 0.176 d.Conelusion Among these five early warning detection models.space-time permutation scan statistic model had the highest efficacy.

Study on the risk factors related to severe acute respiratory syndrome among close contactors in Beijing / 中华流行病学杂志

<p><b>OBJECTIVE</b>To understand the risk factors on severe acute respiratory syndrome (SARS) among their contacts and to develop effective strategy for its control.</p><p><b>METHODS</b>Available epidemiological data of SARS cases and close contacts were reviewed and analyzed by SPSS.</p><p><b>RESULTS</b>Out of the 2195 close contacts, 138 (6.3%) were diagnosed as SARS. Among colleagues and classmates of SARS patients, the infection rate was 0.36% versus 31.71% in contacts among families and hospitals, 0.77% in schools. No one was infected among 459 close contacts to SARS in the working unit.</p><p><b>CONCLUSIONS</b>Among close contacts, factors that facilitating transmission would include: time, extent, frequency and place of contact to the patients, as well as factors related to close contacts as way, time of isolation and age. One of the epidemiological characteristics was that SARS were as clustered in the family among those close contacts. It is important to control the spread of SARS through supervision on the close contacts to patients.</p>