COVID-19 protective measures prevent the spread of respiratory and intestinal infectious diseases but not sexually transmitted and bloodborne diseases
Authors: Shuilian Chen, Xixing Zhang, Yinzhu Zhou, Kewei Yang, Xin Lu
Journal: Journal of Infection (2021)

Protective measures such as social distancing, mask wearing, and hand sanitizing were strictly implemented in China after the lockdown of Wuhan in response to the COVID-19 epidemic. These measures substantially altered everyday activities and also impacted the spread of other infectious diseases.1Fricke L.M. Glöckner S. Dreier M. Lange B. Impact of non-pharmaceutical interventions targeted at COVID-19 pandemic on influenza burden-a systematic review.J Infect. 2021; 82: 1-35https://doi.org/10.1016/j.jinf.2020.11.039Abstract Full Text Full Text PDF PubMed Scopus (82) Google Scholar–3Bright A. Glynn-Robinson A.J. Kane S. Wright R. Saul N. The effect of COVID-19 public health measures on nationally notifiable diseases in Australia: preliminary analysis.Commun Dis Intell. 2018; 2020: 44https://doi.org/10.33321/cdi.2020.44.85Crossref Scopus (20) Google Scholar A few studies have shown marked reductions in cases of influenza, dengue fever, and measles during the COVID-19 epidemic.2Erkhembayar R. Dickinson E. Badarch D. Narula I. Warburton D. Thomas G.N. et al.Early policy actions and emergency response to the COVID-19 pandemic in Mongolia: experiences and challenges.Lancet Glob Health. 2020; 8: e1234-e1e41https://doi.org/10.1016/s2214-109x(20)30295-3Abstract Full Text Full Text PDF PubMed Scopus (0) Google Scholar,4Nascimento M.S. Baggio D.M. Fascina L.P. do Prado C. Impact of social isolation due to COVID-19 on the seasonality of pediatric respiratory diseases.PLoS One. 2020; 15e0243694https://doi.org/10.1371/journal.pone.0243694Crossref PubMed Scopus (47) Google Scholar However, it remains unknown whether there were short- and long-term benefits to COVID-19 control measures for other infectious diseases with distinct epidemiological characteristics. To investigate the effect of the widespread implementation of COVID-19 protective measures on the incidence of other common infectious diseases, we tracked 39 notifiable diseases reported in the Infectious Disease Surveillance System (IDSS) from January 2017 to December 2020 in Changsha. The capital city of China's Hunan province, Changsha has a resident population of 8.4 million and is located about 300 km from Wuhan city. Changsha's first COVID-19 case was confirmed on January 21, 2020. Three days later, Changsha launched the first-level response to a major public health emergency immediately after the lockdown of Wuhan. Quarantine measures such as shelter in place, limited public transportation, and business closures were strictly implemented until early February. The epidemic ended on February 19. Although normal life had been gradually restored after the epidemic, activities such as hospital visits and travel remained seriously affected. In 2019, a significant increase in influenza cases was observed due to improved detection by the widespread use of colloidal gold immunochromatography assay. As a result of COVID-19, the total number of notifiable infectious diseases dropped dramatically in February 2020. However, from May to November, cases increased to 47,351. This represents a 35.15% increase compared to the same period of 2019. We also analyzed disease rate changes in those with over 20 monthly cases in 2017 to 2019. Compared with the average levels of February to April in the previous three years, the cases of most infectious diseases dropped significantly during February to April 2020, except for AIDS. Cases declined most markedly for HFMD (97.00%), influenza (86.67%), mumps (82.29%), acute hemorrhagic conjunctivitis (81.67%), and scarlet fever (80.48%). As time went on, the prevalence of syphilis increased to the same level as the previous three years, while rates of HFMD, tuberculosis, bacillary dysentery, gonorrhea, Hepatitis B, hepatitis C, and other infectious diarrheal diseases were even higher in 2020 (Table 1).Table 1The changes of the number of notifiable diseases reported in 2017–2020.PeriodNumber in 2020Changes in 2020 vs. 3-year average (2017–2019)Changes in 2020 vs. 2019Respiratory diseasesRubellaFeb.–Apr.5-92.06%-97.25%May.–Jun.2-94.69%-98.08%Jul.–Dec.15-56.73%-65.91%Scarlet feverFeb.–Apr.35-80.48%-83.87%May.–Jun.48-81.08%-79.83%Jul.–Dec.222-64.80%-77.80%InfluenzaFeb.–Apr.1678-86.87%-94.00%May.–Jun.1108-76.42%-90.94%Jul.–Dec.3517-88.01%-95.03%PertussisFeb.–Apr.36-53.85%-78.57%May.–Jun.16-78.28%-89.81%Jul.–Dec.31-85.63%-91.80%MumpsFeb.–Apr.304-82.29%-88.82%May.–Jun.583-75.50%-83.16%Jul.–Dec.1699-58.29%-64.42%TuberculosisFeb.–Apr.1100-5.55%-16.35%May.–Jun.103223.00%15.05%Jul.–Dec.27206.11%0.48%Intestinal diseasesHand-foot-and-mouth diseaseFeb.–Apr.80-97.00%-97.59%May.–Jun.616-94.48%-91.57%Jul.–Dec.33378124.72%274.19%Hepatitis EFeb.–Apr.28-34.38%-34.88%May.–Jun.8-70.37%-72.41%Jul.–Dec.44-34.33%-38.03%Other infectious diarrheal diseasesFeb.–Apr.760-71.65%-75.77%May.–Jun.115222.99%0.79%Jul.–Dec.31881.29%-6.18%Typhoid/paratyphoidFeb.–Apr.6-53.85%-60.00%May.–Jun.2397.14%109.09%Jul.–Dec.25-19.35%13.64%Bacillary dysenteryFeb.–Apr.57-15.76%-25.00%May.–Jun.770.87%-4.94%Jul.–Dec.101-41.62%-40.24%Hepatitis AFeb.–Apr.14-36.36%-33.33%May.–Jun.10-40.00%-44.44%Jul.–Dec.425.88%-22.22%Sexually transmitted and bloodborne diseasesGonorrheaFeb.–Apr.149-42.02%-36.60%May.–Jun.2205.10%19.57%Jul.–Dec.84526.18%36.73%Hepatitis CFeb.–Apr.241-31.34%-35.04%May.–Jun.2182.99%2.35%Jul.–Dec.660-6.52%-7.56%Hepatitis BFeb.–Apr.1474-15.56%-26.12%May.–Jun.134111.84%10.73%Jul.–Dec.37953.69%3.35%SyphilisFeb.–Apr.879-32.30%-32.59%May.–Jun.971-0.61%2.21%Jul.–Dec.2706-6.89%-9.83%AIDSFeb.–Apr.730.92%-23.16%May.–Jun.130104.19%94.03%Jul.–Dec.22810.50%5.56%Parasitic and vector-borne diseasesMalariaFeb.–Apr.723.53%0.00%May.–Jun.0-100.00%-100.00%Jul.–Dec.4-76.92%-69.23%Epidemic hemorrhagic feverFeb.–Apr.5463.64%28.57%May.–Jun.6343.18%43.18%Jul.–Dec.46-19.77%-17.86%Dengue feverFeb.–Apr.0-100.00%-100.00%May.–Jun.0-100.00%-100.00%Jul.–Dec.0-100.00%-100.00%Other infectious diseaseAcute hemorrhagic conjunctivitisFeb.–Apr.27-81.67%-85.48%May.–Jun.24-87.46%-91.18%Jul.–Dec.94-73.40%-59.66% Open table in a new tab Taking the transmission route into account, the number of respiratory and intestinal diseases from February to June 2020 dropped dramatically compared to the average levels of the same period in 2017 to 2019. However, in July to December 2020, the number of intestinal diseases increased 100.57% compared to the same time period in 2017 to 2019. The cases of sexually transmitted and bloodborne diseases dropped slightly in February to April 2020, then increased 2.82% in May to December 2020, compared with the three-year average. Cases of parasitic and vector-borne diseases constitute only 0.2% of total notifiable diseases, so the impact of COVID-19 on these conditions remains difficult to evaluate (Fig. 1). As airborne transmission is the dominant route in the spread of COVID-19,5Zhang R. Li Y. Zhang A.L. Wang Y. Molina M.J. Identifying airborne transmission as the dominant route for the spread of COVID-19.Proc Natl Acad Sci U S A. 2020; 117: 14857-14863https://doi.org/10.1073/pnas.2009637117Crossref PubMed Scopus (874) Google Scholar protective measures for containing the COVID-19 epidemic were also effective in combating the spread of other respiratory diseases. This influence remained after the epidemic. The reduced incidence of diseases with other transmission routes during the COVID-19 epidemic may largely be explained by the mass reduction in population mobility due to travel restrictions. According to data from China's Ministry of Transport,6Ministry of transport of the People's Republic of China. 2021 [cited 2021 March 20th]; Available from: http://www.mot.gov.cn/tongjishuju/Google Scholar public transportation passenger volume in Changsha dramatically decreased (88.86%) in February 2020 compared to February 2019, and in July it recovered to 90% of the level seen in 2019. We found that passenger volume was significantly correlated with sexually transmitted and bloodborne diseases (correlation coefficient r = 0.782, p < 0.001), and intestinal diseases (r = 0.418, p = 0.011) during the period between January 2018 and December 2020. Protective measures showed a positive effect on containing the transmission of intestinal diseases, but the influence weakened during the second half of 2020 because of increased social interaction after the lifting of epidemic restrictions. Sexually transmitted and bloodborne diseases were more closely associated with population mobility. The reduction in population mobility during the COVID-19 epidemic presumably led to a reduction in these cases, but the epidemic's influence on sexually transmitted and bloodborne diseases was relatively weaker and shorter-lived compared to its influence on diseases with other transmission routes. The reduction in the number of notifiable infectious diseases cannot be attributed entirely to the implementation of control measures, as patients were less likely to go to the hospital during the epidemic. This may have been due to not being able to make an appointment (during the epidemic, hospitals cancelled or reduced nonurgent outpatient visits) or due to fear of becoming infected with the SARS-CoV-2 virus. To investigate this potential bias, we selected two municipal general hospitals in Changsha and compared their number of outpatients during the COVID-19 epidemic. Our investigation revealed that the number of outpatient visits decreased significantly after the epidemic's onset in late January. Outpatient visits began increasing at the end of February, and by mid-May the number was back to the level of previous years. Outpatient visits were about 26.17% less frequent in February to June compared to the same period of the previous three years. There was, however, the possibility of underreporting of infectious diseases. Our study evaluated the long-term impact of COVID-19 protective measures on the incidence of 39 notifiable diseases for the whole year of 2020. Our analysis revealed that the epidemic had an especially great impact on respiratory and intestinal infectious diseases. Sexually transmitted and bloodborne diseases were more sensitive to the effects of population mobility. The authors declare that they have no competing interests. This research was supported by the National Nature Science Foundation of China (91846301, 82041020, 72025405, 72088101, 71790615), the scientific research project of Hunan Health Committee (202112051105), and the Shenzhen Basic Research Project for Development of Science and Technology (JCYJ20200109141218676).