key: cord-1023587-xqe62xaa authors: Steffen, Robert; Lautenschlager, Stephan; Fehr, Jan title: Travel restrictions and lockdown during the COVID-19 pandemic—impact on notified infectious diseases in Switzerland date: 2020-09-29 journal: J Travel Med DOI: 10.1093/jtm/taaa180 sha: 8ce0f7c5f1250f492024b29c5df4744fe4abc73f doc_id: 1023587 cord_uid: xqe62xaa Based on notification data the impact of the COVID-19 lockdown in Switzerland was assessed. While the incidence of tick-borne encephalitis almost doubled as compared to 2016-2019, a reduction in all other infectious diseases was recorded. The lowest reduction rates (<25%) were noted for legionellosis, hepatitis A, chlamydia infection and gonorrhoea. Based upon epidemic legislation Switzerland on 16 March declared the highest level of pandemic concern and ordered that all non-essential institutions including restaurants, skiresorts, etc. must close the following day. Also meetings exceeding 5 persons were prohibited, but there was no curfew. The authorities recommended to renounce international travel and that those abroad should promptly return. An entry ban for anybody except citizens, residents, cross-border permit holders and essential goods was issued, which has been lifted for travel e.g. to neighbouring countries on 15 June. Taking into account that most Swiss residents returned or were evacuated until the end of March, Switzerland was practically isolated from week 14 (30 March) to 24 (14 June). Within the country the lockdown meant that most non-essential businesses were closed until 11 May, when restaurants opened for parties initially restricted to 4 persons. To assess whether a reduction of imported diseases had occurred in Switzerland during the 11-week isolation period to which we added the initial week after the lockdown we analysed data based on the mandatory reporting to the Federal Office of Public Health. These data are published in weekly Bulletins (https://www.bag.admin.ch/bag/de/home/dasbag/publikationen/periodika/bag-bulletin.html). Additionally we wanted to assess implications of physical distancing within the country. The incidence for the 2020 period was compared to the mean and minimal incidence in the same period in the preceding years 2016 to 2019. As shown in the table we assumed a 'usual incubation period', which could be as long as 4 weeks for hepatitis A and accordingly used the data collected later. Overall, there has been a substantial reduction in almost all recorded infectious diseases (ID) in the 2020 period as compared to earlier years. Typical imported infections and such with respiratory transmission not only had a lower incidence as compared to the average but also to the annual minimum in the previous four years. In contrast, legionella infections, hepatitis A, gonorrhoea in 2020 did not fall below the incidence in every single year in the control period. Among ID with respiratory transmission, the incidence of meningococcal and pneumococcal 6 . In view of the broadly variable incubation period hepatitis B incidence was not assessed. The greatest reduction was recorded in vector borne diseases, which are not endemic in Switzerland. The few cases of malaria reported throughout the period can be explained by potentially long incubation periods and repatriations. In contrast to all above-mentioned infections there has been an increase of reported tick-borne encephalitis even above the 2018 record year 7 as similar to neighbouring countries (Dobler G., TBE-ISW 10 September 2020) many more people during the lockdown went outdoors hiking or performing sports. There are multiple limitations to this assessment of crude ID data submitted first by the diagnostic laboratory and thereafter confirmed by the physician in charge as a rule within 7 days. It may be that particularly ID physicians in these hectic times performed less tests and delayed final diagnosis and reporting. We had no access to the detailed reports often including the date of onset of symptoms and a travel history. Lastly, we cannot demonstrate that the reported changes in incidence are causally associated with the COVID-19 pandemic and the respective preventive measures. Further research needs to be conducted verifying the not only the reliability of the data but also taking into account details after obtaining the necessary clearance. The focus should be on human-to-human transmission and the period of observation should be extended. But already now the conclusion can be drawn thatas expectedthe incidence of (sub)tropical diseases is markedly reduced if the population is prevented of traveling there. Physical distancing had a great impact reducing the risk of respiratory disease transmission. Casual sex continued to be practiced in private circles as documented by the small reduction in gonorrhoea and chlamydia infections. This stands in contrast to a small study conducted in China 8 , but illustrates the need for continued testing and treatment for STI even during a pandemic lockdown 9 . The marked reduction of syphilis and HIV illustrates that these pathogens are transmitted in different higher risk networks 10 . There has been no funding. RS is or in the past three years has been a paid advisor or lecturer to Bavarian Nordic, Global seroprevalence of legionellosis -a systematic review and meta-analysis Impact of public health interventions on seasonal influenza activity during the SARS-CoV-2 outbreak in Korea Positive impact of measures against COVID-19 on reducing influenza in the Northern Hemisphere Online ahead of print Is shigella vaccine needed for travellers and the military? Hepatitis A in der Schweiz Report of the 21st Annual Meeting of the International Scientific Working Group on Tick-Borne Encephalitis (ISW-TBE): TBE − record Sexually transmitted diseases in midst of the coronavirus pandemic Considerations for STI clinics during the COVID-19 pandemic Changing the use of HIV pre-exposure prophylaxis among men who have sex with men during the COVID-19 pandemic in Melbourne