Dengue fever is an acute mosquito-borne viral disease caused by dengue virus (DENV). Temperature may affect the efficiency of the mosquito vectors in spreading DENV. Aedes albopictus mosquitoes were infected orally with a DENV2 suspension and incubated at different temperatures. Subsequently, DENV2 antigen was collected from salivary gland and thorax-abdomen samples on different days postinfection and tested using an immunofluorescence assay to determine the extrinsic incubation period and infection rate. As the temperature increased, the extrinsic DENV2 incubation period in Ae. albopictus gradually shortened, and infection rates showed a tendency to initially increase, followed by a subsequent decrease.

ObjectThis study attempted to explore the effects of vaccination on disease severity and the factors for viral clearance and hospitalization in omicron-infected patients.MethodsThe clinical manifestations of 3,265 Omicron-infected patients (BA.2 lineage variant; the Omicron group) were compared with those of 226 Delta-infected patients (the Delta group). A Multi-class logistic regression model was employed to analyze the impacts of vaccination doses and intervals on disease severity; a logistic regression model to evaluate the risk factors for hospitalization; R 4.1.2 data analysis to investigate the factors for time for nucleic acid negativization (NAN).ResultsCompared with the Delta group, the Omicron group reported a fast transmission, mild symptoms, and lower severity incidence, and a significant inverse correlation of vaccination dose with clinical severity (OR: 0.803, 95%CI: 0.742-0.868, p<0.001). Of the 7 or 5 categories of vaccination status, the risk of severity significantly decreased only at ≥21 days after three doses (OR: 0.618, 95% CI: 0.475-0.803, p<0.001; OR: 0.627, 95% CI: 0.482-0.815, p<0.001, respectively). The Omicron group also reported underlying illness as an independent factor for hospitalization, sore throat as a protective factor, and much shorter time for NAN [15 (12,19) vs. 16 (12,22), p<0.05]. NAN was associated positively with age, female gender, fever, cough, and disease severity, but negatively with vaccination doses.ConclusionBooster vaccination should be advocated for COVID-19 pandemic-related control and prevention policies and adequate precautions should be taken for patients with underlying conditions.

Severe acute respiratory syndrome coronavirus 2 breakthrough infection in highly vaccinated populations raises study on the effectiveness for inactivated vaccine, including effectiveness of the vaccine dose, the continuance of effectiveness, the effectiveness against severe/critical coronavirus disease 2019 and against secondary attacks. A population of 10 870 close contacts were investigated in a Delta variant's epidemic. The effectiveness of vaccination was estimated in a test‐negative case–control study. In addition, serum was used to detect neutralizing antibodies, to explore their correlation to effectiveness. The vaccine effectiveness (VE) values were estimated for populations aged 12 years or older. The overall adjusted VE was 56.2% and a two‐dose vaccine was more effective than a one‐dose vaccine (56.7% vs. 43.8%). In addition, the population that got the second dose vaccine within 2 months showed higher VE than the population vaccinated for longer than 2 months (61.5% vs. 52.3%). Among the population who vaccinated 2 doses or within 2 months, a higher level of neutralizing antibodies was observed. For infected cases, vaccinated populations showed lower rates of transmission (2.63% vs. 4.36%). Further, those vaccinated cases, who were not found causing transmission, had a higher level of antibodies. The study provided a full view of the effectiveness of inactivated vaccines in a real‐world setting. The time‐related VE against infection and lower transmission of breakthrough vaccinated cases were observed, which may indicate that a necessity of a booster vaccine to maintain the effectiveness and high level of neutralizing antibody.

Background: Babesiosis is a tick-borne disease that mainly affects small mammals and it has been reported in at least ve provinces in China. However, the host range and geographical distribution of the parasite in Fujian Province are unclear. Therefore, this study aimed to investigate the prevalence and genetic characteristics of Babesia in Fujian Province, Southeast China, between 2015 and 2020.Methods: Rodent blood samples were collected from 26 different surveillance sites across Fujian Province. Genomic DNA was extracted to screen for Babesia infection using polymerase chain reaction (PCR) ampli cation, based on 18S rRNA. DNA samples from 316 domestic goats, 85 water buffalo, 56 domestic dogs, and 18 domestic pigs were examined. The prevalence of Babesia was statistically analyzed using the Chi-square test or Fisher's exact test. A phylogenetic tree was constructed using MEGA 5.0 by gene sequence alignment.Results: Babesia infections were found in 3.96% (43/1,087) of rodents and 1.26% (6/475) of other mammals. Multivariate logistic regression analysis revealed that irrigated cropland, shrubs, and forests were risk factors for Babesia microti infections. The infection rates among domestic pigs, dogs, and goats were found to be 5.56%, 1.79%, and 1.27%, respectively, and no infection was found in water buffalo. Sequencing (18S rRNA gene) revealed that rodents were infected with Babesia (sensu lato) while other mammals were infected with Babesia (sensu stricto). Conclusions:The results indicate that there is wide geographical distribution and phylogenetic relationship of Babesia in Southeast China. This study suggests that mammals, especially wild rodents, are the main natural hosts of Babesia in Fujian. Our ndings provide a solid foundation for public health o cials to develop Babesia prevention and control measures.

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