Analysis of cases of reinfection of past SARS-CoV-2 patients in Pudong New Area of Shanghai / 上海预防医学

ObjectiveTo identify the rate， population characteristics， and vaccination history of repeat infections among previously infected people in the current epidemic based on the rate of repeat infection and population characteristics of different mutant strains at different times in Pudong New Area of Shanghai， and to provide reference for the prevention and control strategies of novel coronavirus repeat infections. MethodsA total of 9 250 investigated subjects were randomly selected from the new cases of asymptomatic infection and confirmed cases reported by Pudong New Area from March to May 2022. The investigation mainly focused on demographic characteristics， nucleic acid or antigen test results， and symptoms after infection. The repeat infection rates among different populations were compared， and logistic regression was used to analyze the impact of gender， age， and vaccination status on repeat infections. ResultsThe survey sample of 9 250 people had a response rate of 81.85%. There were 4 043 males （53.40%） and 3 528 females （46.60%）， with a median age of 34 years old （P25， P75： 7， 61）. The overall vaccine uptake rate was 59.44% （4 500/7 571）. In December of 2022， there were 563 cases of repeat infection， with an infection rate of 7.44%. The lowest rate of repeat infection was seen in the 3‒ year-old group （2.86%） and the highest rate in the 30‒ year-old group （12.42%）， with significant differences between different age groups. The repeated infection rate for those who had completed their vaccinations was significantly lower （6.57%） compared to those who had not （7.11%）. The age groups of 3‒ years， 70‒79 years， as well as individuals who completed full vaccination and received booster shots were protective factors against repeat infections. ConclusionThe overall rate of reinfection among the infected in Shanghai during the spring of 2022 was low in the outbreak of the Omicron variant， and the rate of reinfection in the 3‒ year-old group was significantly lower than in other age groups. Completing the full course of vaccination significantly reduces the risk of reinfection. Although the reinfection rate is high in individuals who received booster shots， it remains a mitigating factor compared to those who do not receive the vaccine. It is recommended to continue monitoring reinfections in key populations and further strengthen immunization efforts.

Virus spectrum of inpatients with acute respiratory infection in Pudong New Area , Shanghai / 公共卫生与预防医学

Objective To understand the viral spectrum of inpatients with acute respiratory infection in Pudong New Area, and to explore the composition of pathogens in hospitalized children and adults. Methods Samples of acute respiratory infection cases from 10 medical institutions were collected from 2011 to 2020 and tested for human influenza virus, human adenovirus, rhinovirus, human parainfluenza virus, respiratory syncytial virus, human coronavirus, human metapneumovirus and human boca virus. Results A total of 3 145 inpatients were monitored, with a median age of 61 years. The positive rate of any virus was 32.43% (1 020/3 145), and the single virus infection accounted for 85.98% (877/1 020). In single virus infection, the positive rate of human influenza virus was the highest (9.67%, 304/3 145), with influenza A (80.26%, 244/304) as the main virus. The second was rhinovirus (3.97%, 125/3 145). The positive rate of any virus in different age groups was statistically significant (χ2=103.38，P2=123.06，P2=90.37，P<0.001). Conclusion The positive rate of virus in hospitalized patients with acute respiratory infection is relatively high in Pudong New Area, Shanghai, with human influenza virus being the main virus. The virus spectrum of hospitalized children and adults is inconsistent. In the future, in-depth research should be strengthened, focusing on the distribution of pathogens in different populations and seasonal prevention and treatment.

Seasonal characteristics and etiologic features of the cluster of fever in Pudong New Area of Shanghai in 2013-2021 / 公共卫生与预防医学

Objective To understand the seasonal and etiological characteristics of the epidemic situation of cluster fever in Pudong New Area, Shanghai, and to provide a scientific basis for the formulation of prevention and control strategies. Methods The epidemic data of cluster fever in Pudong New Area of Shanghai from 2013 to 2021 were collected, and the data were analyzed by concentration degree and circular distribution methods. Results From 2013 to 2021, there were 109 cases of cluster fever reported in Pudong New Area, with primary schools reporting the most cases, 77 cases (70.64%). The M value was 0.59. Circular distribution results showed that angle dispersion index r value was 0.54, the average angle was 357.32°, and the average angle of Rayleigh’s test Z value was 32.07. The peak day was December 28, and the peak period was from October 25 to March 3 of the following year. The cluster of fever in Pudong New Area was mainly caused by influenza virus. Most cases were single pathogen infection, and some were double pathogen infection. Influenza A virus had the highest detection rate in both single pathogen infection and double pathogen infection. Conclusion Primary schools are the focus of prevention and control of the cluster of fever in Pudong New Area. The epidemic situation of cluster fever has a strong seasonal characteristic, and the peak of incidence is from late October to early March of the next year. Respiratory pathogens such as influenza virus are the main causes of the epidemic situation.

Epidemiological characteristics of norovirus infectious diarrhea in Pudong New Area of Shanghai in 2015-2019 / 公共卫生与预防医学

Objective To understand the epidemiological characteristics of norovirus infectious diarrhea in Pudong New Area of Shanghai, and to provide reference for prevention and control of diarrhea caused by norovirus. Methods Epidemiological data and stool samples from diarrhea cases of 15 hospitals in 2015-2019 years were collected. The two subtypes of norovirus G I and G II were detected by RT-PCR and analyzed. Results A total of 9 397 diarrhea samples were collected in 2015-2019 years, and 1 938 positive norovirus samples were detected, with a positive rate of 20.62%. The majority of serotypes were GII (88.60%). Diarrhea caused by norovirus occurs all year round, with high incidence season in 2-3and 10-12 months every year. There was no significant difference in the positive rate of norovirus between different sexes（χ2=2.611，P=0.106）. The positive rate of the 15-64 year old group was higher than that of the 0-14 year old group and the 65 year old and above group（χ2=153.634，P<0.001）. The highest positive rate was for cadres /worker/ business services / teachers / medical staff / drivers. The positive rate of norovirus in diarrhea cases with vomiting was significantly higher than that in patients without vomiting. Conclusions Diarrhea caused by norovirus is related to season, age and occupation. Because there is no effective antiviral drugs and vaccine prevention, continuous monitoring should be carried out and targeted preventive measures should be carried out according to epidemiological characteristics.

Infection status and virulent genes of Aeromonas in diarrhea patients in Pudong New Area, Shanghai / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate the infection status and virulent genes of Aeromonas in patients with acute diarrhea in Pudong New Area, Shanghai.</p><p><b>METHODS</b>In 2012, stool samples were collected from diarrhea patients in 12 sentinel hospitals in Pudong for the detections of 13 pathogens causing diarrhea, and the detections of 5 diarrhea related virulent genes were conducted for Aeromonas isolates.</p><p><b>RESULTS</b>A total of 101 patients were infected with Aeromonas in 2533 patients (4.0%). A total of 101 Aeromonas strains were isolated, including 17 Aeromonas hydrophila strains (18.8%), 44 Aeromonas veronii biovar sobria strains (52.5%) and 12 Aeromonas caviae strains (29.7%). And 44 coinfections with other pathogens were detected. Aeromonas infection mainly occurred in summer and in people aged ≥20 years. Among the patients infected with Aeromonas, 71 (70.3%) had watery diarrhea, 20 (19.8%) had vomiting and 11 (10.9%) had fever. Virulent genes detection showed that 95.0% of the Aeromonas. strains carried virulent genes, and the detection rates of hlyA, aerA, act, alt, and ast genes were 5.9%, 6.9%, 67.3%, 42.6% and 13.9%, respectively.</p><p><b>CONCLUSIONS</b>High incidence of Aeromonas infection was found in the patients with acute diarrhea in Pudong, and a high proportion of coinfections with other pathogens was detected too. Most Aeromonas strains carried virulent genes, and the distribution varied.</p>