Objective: To analyze the status of follow-up cell testing of HIV/AIDS cases among young students aged 15-24 in Guangdong Province from 2008 to 2019. Methods: Using the historical database downloaded from the AIDS Comprehensive Prevention and Control Information System from January 1, 2018 to December 31, 2019, eligible newly discovered cases were screened by year and were linked with follow-up database. Joinpoint regression model and trend test were used to explore the annual changes in the follow-up and CD4 testing status, and Logistic regression was used to analyze relevant influencing factors. Results: The number of infected students showed a rapid upward trend before 2015(APC=41.7，β=0.3，P<0.01), and the growth rate slowed down(APC=3.6，β=-0.3，P<0.01). The proportion of follow-up and CD4 testing completed within one year increased from 58.3% in 2008 to 93.6% in 2019, and the timely detection rate increased from 33.3% in 2008 to 86.2% in 2019. The Cochran Armitage trend test was statistically significant. Pairwise comparison test showed time trends of the idnex differed in regions and education groups (Z=4.7，8.7，9.8，P<0.01). The Pearl River Delta region, cases from other cities in the province, with precise transmission routes, from voluntary counseling and testing, and cases flowing within the province, the proportion of follow up and testing completed within one year is relatively high (P<0.05). Conclusion The growth rate of HIV/AIDS cases among young students aged 15-24 in Guangdong Province has slowed down in recent years. The route of infection, source and flow of cases affect follow-up and testing compliance. And to do a good job of referrals for off-site mobility, and explore and promote student-friendly VCT service models.

Objective: To understand the prevalence of HIV testing and related factors among young students who had sex in Guangdong Province, in order to provide evidence for relevant education programs and HIV testing promotion in young students. Methods: From September to December 2022, a convenient sampling method was used to select 48 749 young students from 16 universities and mechanic colleges in 6 cities including Guangzhou, Shantou, Maoming, Huizhou, Dongguan, and Zhongshan in Guangdong Province for online questionnaire survey. A total of 2 971 students who ever had sexual experiences were screened out, and the HIV testing situation and related factors were investigated by using the questionnaire designed by AIDS Prevention and Education Project for College Students of China STD and AIDS Prevention Association.The influencing factors of HIV testing were analyzed using Chi square test and multiple Logistic regression model. Results: Among students who had sexual experiences, 11.92% (354/2 971) were tested for HIV. The results of multivariate Logistic regression analysis showed that among young sexual students, using psychoactive substances during sexual activity in the last 1 year ( OR =7.70), having first sex with the same sex ( OR =3.87), having commercial sex ( OR =2.37), having heard of PEP ( OR =2.20), having a high level of self assessed understanding of HIV testing ( OR =1.73), inconsistent use of condoms ( OR =1.56), being aware of HIV infection ( OR =1.53), being aware of HIV knowledge ( OR =1.51) were more likely to test for HIV, and females ( OR =0.39) were less likely to test for HIV ( P < 0.05). Conclusions The proportion of HIV testing is low among sexually active young students in Guangdong Province. Targeted interventions should be tailored to promote HIV testing coverage.

Objective:To analyze the epidemiological characteristics of the cases firstly reported as "asymptomatic infection of COVID-19" in Guangdong province.Methods:The follow-up observation method was used to continuously track and observe the cases firstly reported as "asymptomatic patients with COVID-19" in Guangdong province from January 14 to March 31, 2020. The epidemiological data of the cases were collected to analyze their epidemiological characteristics, outcome and influencing factors.Results:From January 14 to March 31, 2020, a total of 325 cases were firstly reported as "asymptomatic infections of COVID-19" in Guangdong province. The epidemic curve of asymptomatic infection cases was similar to that of confirmed cases, and it had two peaks. The first peak was from January 27 to February 5, and the second peak was from March 17 to March 26. Of the 325 cases, 184 (56.6%) were subsequently converted to confirmed cases. These cases were defined as incubation period asymptomatic infection cases. The age median of the cases was 40 years, and 93.5% (172/184) of the cases showed symptoms within 3 days after the first positive nucleic acid tests were conducted, and 141 (43.4%) of the 325 cases remained asymptomatic status until they were cured and discharged. They were inapparent infection cases, accounting for 8.6% (141/1 642) of those diagnosed with COVID-19 in Guangdong province during the same period. The age median of inapparent infection cases was 27 years. The median of the interval between the first positive nucleic acid test and discharge was 14 days. Up to 90.8% (138/141) of the inapparent infection cases were discharged for centralized medical observation within 28 days. The longest interval between the first positive nucleic acid test and the last positive nucleic acid test was 73 days. The positive rate of nucleic acid test was 0.3% in close contacts of inapparent infection cases and 2.2% in close contacts of incubation period asymptomatic infection cases. There were significant differences in age distribution and source of infection between incubation period asymptomatic infection cases and inapparent infection cases ( P<0.05). Old age was the risk factor for the conversion of firstly reported asymptomatic infection cases to confirmed cases. Compared with the 0-19-year-old group, The patients aged 40-59 years and 60 years and above were more likely to become confirmed cases. The OR (95 %CI) values were 2.730 (1.380-5.402) and 5.302 (2.199-12.783), and P values were 0.004 and 0.000, respectively. People being infected in China were more likely to become confirmed cases ( OR=7.121, P=0.000). Conclusions:There were asymptomatic infection cases among patients diagnosed with COVID-19. The infectiousness of incubation period asymptomatic infection cases might be stronger than that of inapparent infection cases. The proportion of younger cases among asymptomatic infection cases was higher than that of the confirmed cases. Old age and domestic infection were the risk factors for the conversion of asymptomatic infection cases to confirmed cases, to which more attention should be paid. Further serological investigations are needed to provide a basis for the development of COVID-19 prevention and control strategies.

Objective:To investigate the risk perception for risky behavior of HIV/AIDS infection among young students and to analyze the related influencing factors.Methods:A cross-sectional survey was conducted in 5 different types of Guangzhou colleges from September to November 2021, in which convenience sampling and a minimum number of classes per grade and 600 samples per school were used according to the national unity program. Disordered multi-classification logistic regression was used to construct a risk perception model and analyze influencing factors in different risk perception levels.Results:A total of 7 346 young students were surveyed, and most rated themselves at low risk of HIV/AIDS infections (90.58%, 6 654/7 346). A total of 89.10% (6 545/7 346) of subjects' perception of their HIV/AIDS infection risk was consistent with their risk behavior, while 10.90% (801/7 346) was inconsistent. Among those inconsistent subjects, 19.10% (153/801) showed underestimating their risk , while 80.90% (648/801) seen overestimating their risk. Disordered multi-classification logistic regression analysis showed that, after controlling for other factors, compared with the non-sexual group, respondents whose first sex age under 18 had a higher rate of underestimating their risk of infection ( OR=129.39, 95% CI: 73.28-228.48), as well as a higher rate of overestimated their risk of infection ( OR=1.76, 95% CI: 1.04-2.99). First sexual intercourse at age 18 or older was a risk factor for underestimating risk ( OR=70.56, 95% CI: 42.72-116.53), but was not statistically associated with overestimating risk. Being female, other school type, non-heterosexual orientation, and self-rated HIV-related knowledge as fair or no knowledge were risk factors for overestimating risk but were not statistically associated with underestimating risk. Conclusions:Overall, young students in universities of Guangzhou have a good risk perception of HIV/AIDS infection. Individual factors, education factors and sexual experience will influence students' risk perception of HIV/AIDS infection. Raising the awareness rate of HIV/AIDS knowledge and delaying the age of first sexual intercourse will improve the risk perception ability of young students.

Objective:To explore high-risk sexual behaviors of HIV/AIDS and related factors in young students in Guangzhou.Methods:A cross-sectional survey was conducted in 5 different types of Guangzhou colleges by convenience sampling with minimum number of classes per grade and 600 samples per school from September to November 2021. The R 4.2.2 software was used to consolidate databases. Simultaneously, a logistic regression model and a decision tree algorithm model, stratifying by whether sexual behaviors had occurred before, were constructed. In each layer, the prediction performance of the two models was evaluated through area under receiver operating characteristic and the confusion matrix, and then the model with high prediction performance was retained.Results:A total of 7 346 students were surveyed. The proportion of the respondents reporting sexual experience were 9.08% (667/7 346), in whom 26.24% (175/667) had risky sexual activity in the past year. The decision tree algorithm model performs well in predicting whether high-risk sexual behaviors have occurred in the past year. When the complexity parameter value is 0.018, and nsplit reaches 4, which means there are 5 leaf nodes in the model, the cross error of the tree will be the smallest. The first best grouping variable in the decision tree was whether to use condoms throughout the first sexual behavior. If condoms were used at their sexual debut, but homosexual practices have occurred in the past year, the probability of risky sexual behavior will increase. If homosexual practices have not occurred in the past year, but the age of sexual debut was below 18 years old while the period of HIV education was after high school, the probability of risk sexual behavior will also increase.Conclusions:AIDS-related risky behaviors of young students still deserved attention. The experience of sexual debut and whether AIDS-related health education has been received before the sexual debut were significant predictors for the occurrence of high-risk sexual behavior. The decision tree algorithm model has particular applicability for predicting and screening potential risk populations.

AIM: To assess the accuracy of predicting intraocular lens(IOL)power after myopic refractive surgery using the Pentacam system's true net power(TNP)in the 3 mm zone combined with the SRK/T formula [i.e. TNP 3 mm(SRK/T)].METHODS: Retrospective study. This study enrolled 35 cases(50 eyes)of patients undergoing cataract surgery after laser assisted in situ keratomileusis(LASIK)or photorefractive keratectomy(PRK)from July 2019 to December 2021. Preoperatively, IOL power of 50 eyes, 34 eyes and 41 eyes was calculated by TNP 3 mm(SRK/T), Barrett True-K and Olsen 2 formulas, respectively, with at least 2 formulas used to calculate IOL power for each patient. The actual diopter was recorded 3 mo postoperatively. Prediction errors(PE)of IOL power were compared among the three calculation methods, and the proportion of eyes with PE within ±0.5 D and ±1.0 D was analyzed.RESULTS: The PE at 3 mo postoperatively for TNP 3 mm(SRK/T), Barrett True-K, and Olsen 2 was -0.02±0.63, -0.54±0.80, and 0.25±0.80 D, respectively(P<0.001). The proportions of PE within ±0.5 D were 66%(33/50), 44%(15/34)and 37%(15/41), respectively(P<0.05); the proportions of PE within ±1.0 D were 88%(44/50), 71%(24/34)and 80%(33/41), respectively(P>0.05).CONCLUSION: The Pentacam TNP 3 mm(SRK/T)method is simple to operate and provides accurate calculation of IOL power after corneal refractive surgery.