Symptomatic and Asymptomatic SARS-CoV-2 Infection and Follow-up of Neutralizing Antibody Levels.

Objective: To investigate neutralizing antibody levels in symptomatic and asymptomatic patients with coronavirus disease 2019 (COVID-19) at 6 and 10 months after disease onset.

Methods: Blood samples were collected at three different time points from 27 asymptomatic individuals and 69 symptomatic patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Virus-neutralizing antibody titers against SARS-CoV-2 in both groups were measured and statistically analyzed.

Characterization of Two Human Monoclonal Antibodies Neutralizing Influenza A H7N9 Viruses.

H7N9 was a cause of significant global health concern due to its severe infection and approximately 35% mortality in humans. By screening a Fab antibody phage library derived from patients who recovered from H7N9 infections, we characterized two human monoclonal antibodies (HuMAbs), HNIgGD5 and HNIgGH8. The epitope of these two antibodies was dependent on two residues in the receptor binding site at positions V186 and L226 of the hemagglutinin glycoprotein.

[Investigation on measles cases of new genotype D8 in Beijing, 2013].

Objective: To investigate the epidemiological characteristics of measles cases of new genotype D8 in Beijing from January to June, 2013.

Methods: Epidemiological survey and descriptive analysis was conducted.

Results: 661 suspected measles were reported from January to June, 2013.

[Analysis of measles immunity level in persistent populations in Beijing, 2012].

Objective: To analyze the measles immunity level of persistent population in Beijing.

Methods: A total of 2125 objects from 10 age groups, who had been living in Beijing for over 6 months, were selected from urban and rural areas in Beijing in 2012. Demographic characteristics, history of measles and vaccine immunization were investigated by questionnaire.

[Survey on seroepidemiological status and vaccine coverage of hepatitis B among children in Chaoyang district of Beijing in 2010].

Objective: To explore seroepidemiological status and vaccine coverage of hepatitis B in children aging under 15 years old in Chaoyang district of Beijing.

Methods: A total of 1602 children aging under 15 years old, residents or floating population who had lived here more than six months, were randomly selected by multistage cluster sampling, from Chaoyang district of Beijing in year 2010. The demographic information and vaccine coverage of hepatitis B vaccine (HepB) were collected by self-designed questionnaire.

[Study on family aggregation and risk factors of hepatitis B virus transmission in Chaoyang district, Beijing].

Objective: To explore the family aggregation and risk factors of hepatitis B virus (HBV) transmission in Chaoyang district of Beijing.

Methods: A total of 5266 families were randomly selected for the multi-stage cluster sampling study in Chaoyang district of Beijing in 2010. The family members who aged between 1 and 70 years old and lived constantly in Beijing for over half a year, were recruited as subjects.

[Prevalence of hepatitis B in Chaoyang district, Beijing in 2010].

Objective: To study the prevalence of hepatitis B infections and carrier status among general population in Chaoyang district, Beijing in 2010.

Methods: From May to December 2010, 14 491 subjects over 12 months old were selected by multistage random cluster sampling method from residents in Chaoyang district, Beijing. Five millilitre venous blood specimens were collected from these subjects to test hepatitis B virus antigens and antibodies.

[Study of immunogenicity after primary vaccination by different sequential program of inactivated poliovirus vaccine and oral poliovirus vaccine].

Objective: To evaluate immunogenicity after primary vaccination by different sequential program of inactivated poliovirus vaccine (IPV) and oral poliovirus vaccine (OPV).

Methods: 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.

[The epidemiological impact of varicella vaccination in kindergartens, primary and secondary schools in Beijing].

Objective: To study the epidemiological impact of varicella vaccine vaccination on kindergartens and school children in Beijing.

Methods: 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.

[A case-control study of the transmission of pandemic influenza A (H1N1) virus in families].

Objective: To explore the characteristics of transmission of pandemic influenza A/H1N1, and to analyze the possible factors of influencing transmission in families and to provide scientific evidence for formulating strategies of H1N1 prevention and control.

Methods: A 1:2 matched case-control study was conducted. The case was defined as a household with 2 or more cases and the control was defined as that with 1 case.

[Epidemiological characteristics of infection for close contacts of pandemic (H1N1) 2009 in Beijing].

Objective: To examine the epidemiological characteristics of infection for close contacts of pandemic (H1N1) 2009 and to provide scientific evidence for preparedness and response for the next pandemic.

Methods: A total of 613 index cases with clear information of close contacts and their 7099 close contacts, determined between May 16 and September 15, 2009, were included in this study. Based on data of epidemiological investigation, sampling and test of index cases and close contacts, the characteristics of infection for close contacts were described.

[Quantitative evaluation on the effectiveness of prevention and control measures against pandemic influenza A (H1N1) in Beijing, 2009].

Objective: To quantitatively evaluate the effectiveness of prevention and control measures against pandemic influenza A (H1N1) in Beijing, 2009 and to provide evidence for developing and adjusting strategies for prevention and control of the disease.

Methods: Considering the seasonality and the number of vaccination on pandemic influenza A (H1N1), data regarding pandemic influenza A (H1N1) in Beijing were collected and analyzed. Based on the dynamics of infectious disease transmission, a quantitative model for evaluation of prevention and control measures was developed.

[The significance of different sample types in study of pandemic A (H1N1) influenza diagnosis].

Objective: To explore the value of different types of samples, including throat swabs, stools, bloods in pandemic A (H1N1) influenza diagnosis and virus shedding patterns.

Methods: From May to June in 2009, 135 samples were collected from 23 confirmed cases of pandemic influenza A (H1N1) infection, including 99 throat swabs, 14 stools, 11 bloods, 1 respiratory tract washing from 13 confirmed cases and 10 blood samples from other confirmed cases. The virus was detected by real-time RT-PCR, the antibody was detected by haemagglutination inhibition assay.

[Pandemic influenza A (H1N1) virus infection factors among healthcare workers - a case-control study].

Objective: To explore factors related to pandemic influenza A (H1N1) virus infection among healthcare workers.

Methods: H1N1 influenza confirmed cases of health workers in hospital of Beijing from Aug 30th 2009 to Jan 31st 2010 were included. A 1:4 matched case-control study was conducted with 54 healthcare workers who were infected by influenza A(H1N1) virus and 216 matched controls who were not infected.

[Study on the cellular and humoral immunity effect of recombinant Chinese hamster ovary cell hepatitis B vaccine in adults].

Objective: To evaluate the cellular and humoral immunity effect of 10 µg and 20 µg recombinant Chinese hamster ovary (CHO) cell hepatitis B vaccine in adults by randomized double-blind controlled trials.

Method: A total of 642 adults aged 18 - 45 years old, non-vaccinated against hepatitis B, and hepatitis B five blood indicators negative were selected as the study subjects. The study subjects were randomly divided into two groups and each group had 321 subjects.

[Analysis of adverse events following 2009 influenza A (H1N1) vaccinoprophylaxis in Beijing].

Objective: To evaluate the safety of 2009 influenza A (H1N1) vaccine based on mass immunization initiative in Beijing.

Method: 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.

[Estimation on the real number of novel influenza A (H1N1) cases, Beijing, 2009].

Objective: To estimate the real number of novel influenza A (H1N1) infection in Beijing, 2009.

Methods: A multiplier model (Impact 2009 v 1.0 software) based on Monte Carlo approach was used to estimate the real number of novel influenza A (H1N1) based on the number of influenza-like illness (ILI) cases, novel influenza A (H1N1) positive rate among ILI cases and rate on clinical visit of ILIs in secondary and tertiary hospitals.

[Etiological characteristics of influenza A (H1N1) 2009 virus in Beijing].

Objective: To analyze the results of detection on influenza A (H1N1) 2009 virus in Beijing from May 2009 to December 2009 and to understand the epidemiologic characteristics during the pandemic period.

Methods: The study was conducted from the May 1 to December 27, 2009. A total of 101 852 throat swab samples were detected with the real-time RT-PCR assay by the Beijing Network Laboratory.

[A survey on serological epidemiology of influenza A (H1N1) 2009 in Beijing].

Objective: To investigate the immunological level against influenza A (H1N1) 2009 in Beijing and provide evidence to evaluate the developing trend of the disease.

Methods: Between Nov. 27, 2009 and Dec.

[Study on the immuno-effects and influencing factors of Chinese hamster ovary (CHO) cell hepatitis B vaccine among adults, under different dosages].

Objective: To evaluate the immuno-effect and related influencing factors on 10 µg and 20 µg Chinese hamster ovary (CHO) cell hepatitis B vaccine, using the randomized double-blind controlled trials in adult population.

Methods: A total of 642 adults aged 18 - 45 years old, non-vaccinated against hepatitis B, and negative on five blood indicators for hepatitis B, were selected as the study objects from four districts in Beijing. The study objects were randomly divided into two groups, and then accepted 10 µg and 20 µg recombinant CHO hepatitis B vaccination by 0 - 1 - 6 month schedule.

Serologic survey of pandemic influenza A (H1N1 2009) in Beijing, China.

Objective: To examine the frequency and distribution of antibodies against pandemic influenza A (H1N1 2009) [H1N1] in populations in Beijing and elucidate influencing factors.

Methods: In January 2010, a randomized serologic survey of pandemic influenza A (H1N1 2009) was carried out. Six districts that were randomly selected with a total of 4601 participants involved in the survey have their antibody level tested by hemagglutination inhibition assay.

[Herd immunity against new influenza A (H1N1) in pre-vaccinated residents aged over 5 years in Beijing].

Objective: To explore the herd immunity against influenza A (H1N1) in pre-vaccinated residents aged over 5 years, and therefore to provide data for vaccination policies in high risk populations.

Methods: From October to December 2009, Beijing CDC conducted a serum survey of the novel influenza A (H1N1) in the local residents, stratified in 10 age groups between 5 years to over 60 years, without H1N1 vaccination history and disease history. Hemagglutination inhibition (HI) assays were performed at Beijing CDC.

[Investigation on the source of the first human of avian influenza A (H5N1) case in Beijing].

Objective: To investigate the source of the first human case of avian influenza A (H5N1) infection in Beijing.

Methods: Interviewing the relatives of the case and other key persons, collecting and detecting samples of related biological, epidemiological and environmental data of the case were conducted. Later, the infection source was thoroughly investigated.