Behavioral-immune-system research has illuminated how people detect and avoid signs of infectious disease. But how do we regulate exposure to pathogens that produce no symptoms in their hosts? This research tested the proposition that estimates of interpersonal value are used for this task. The results of three studies ( N = 1,694), each conducted using U.S. samples, are consistent with this proposition: People are less averse to engaging in infection-risky acts not only with friends relative to foes but also with honest and agreeable strangers relative to dishonest and disagreeable ones. Further, a continuous measure of how much a person values a target covaries with comfort with infection-risky acts with that target, even within relationship categories. Findings indicate that social prophylactic motivations arise not only from cues to infectiousness but also from interpersonal value. Consequently, pathogen transmission within social networks might be exacerbated by relaxed contamination aversions with highly valued social partners.

ObjectiveMycoplasma pneumoniae (M. pneumoniae) is an important pathogen of community acquired pneumonia. With the outbreak of coronavirus disease 2019 (COVID-19), the prevalence of some infectious respiratory diseases has varied. Epidemiological features of M. pneumoniae in children from Beijing (China) before and during the COVID-19 pandemic were investigated.MethodsBetween June 2016 and May 2021, a total of 569,887 children with respiratory infections from Children’s Hospital Affiliated to Capital Institute of Pediatrics (Beijing, China) were included in this study. M. pneumoniae specific-IgM antibody in serum specimens of these patients was tested by a rapid immunochromatographic assay kit. The relevant clinical data of M. pneumoniae-positive cases were also collected, and analyzed by RStudio software.ResultsThe results showed that 13.08% of collected samples were positive for M. pneumoniae specific-IgM antibody. The highest annual positive rate was 17.59% in 2019, followed by 12.48% in 2018, 12.31% in 2017, and 11.73% in 2016, while the rate dropped to 8.9% in 2020 and 4.95% in 2021, with significant difference. Among the six years, the positive rates in summer and winter seasons were significantly higher than those in spring and autumn seasons (p < 0.001). The positive rate was the highest in school-age children (22.20%), and lowest in the infant group (8.76%, p < 0.001). The positive rate in boys (11.69%) was lower than that in girls (14.80%, p < 0.001). There were no significant differences in different seasons, age groups, or genders before and during the COVID-19 pandemic (p > 0.05).ConclusionsOur study demonstrated that an M. pneumoniae outbreak started from the summer of 2019 in Beijing. After the COVID-19 pandemic outbreak in the end of 2019, the M. pneumoniae positive rates dropped dramatically. This may be due to the restrictive measures of the COVID-19 pandemic, which effectively controlled the transmission of M. pneumoniae. The relationships between M. pneumoniae positive rates and season, age, and gender were not statistically significant before and during the COVID-19 pandemic.

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Behavioral immune system research has illuminated how people detect and avoid signs of infectious disease. But how do we regulate exposure to pathogens that produce no symptoms in their hosts? This manuscript tests the proposition that estimates of interpersonal value are used for this task. Three studies (N = 1694), each conducted using U.S. samples, are consistent with this proposition: people are less averse to engaging in infection-risky acts not only with friends relative to foes, but also with honest and agreeable strangers relative to dishonest and disagreeable ones. Further, a continuous measure of how much a person values a target covaries with comfort with infection-risky acts with that target, even within relationship categories. Findings indicate that social prophylactic motivations arise not only from cues to infectiousness, but also interpersonal value. Consequently, pathogen transmission within social networks might be exacerbated by relaxed contamination aversions with highly valued social partners.

The modern world affords unprecedented opportunities for individuals to express moral sentiments. The widespread distribution of one specific type of sentiment – outrage – has consequences for social and political harmony. The current investigation contributes to better understanding these consequences by examining what types of aggression people expect from the outraged. Further, it delineates how these expectations are shaped by the emotion used to express outrage. Three pre-registered studies (N’s = 800, 1630, 1100) revealed that people infer different types of aggression from individuals who expressed anger nonverbally compared with those who expressed disgust nonverbally. Perceptions that the outraged individual was angry corresponded with expectations of direct aggression rather than indirect aggression, whereas perceptions that the outraged individual was disgusted corresponded with expectations of indirect aggression rather than direct aggression. These results revealed that the distinct emotions used to communicate outrage shape observers’ expectations of how moral conflicts will unfold.