What does it mean that COVID-19 is classified as a disease that is dangerous to public health and to society under the terms of the Communicable Diseases Act?
Classifying the disease as dangerous to public health and to society are steps toward enhanced preparedness in Sweden. The Public Health Agency believes that the legislation needs to be in place should there be transmission in the community. The risk of this happening is currently considered to be very high.
The virus being classified under the Communicable Diseases Act enables the necessary preventive measures to be taken to handle the spread of the virus in the community. For diseases dangerous to public health and to society, there are a number of possible interventions including quarantine, isolation, health screenings on arrival in the country, and areas being closed off. Depending on the intervention, the decision is made either by the regional officers for communicable disease control or the Public Health Agency of Sweden.
How can a negative test result, which indicates that you are well, at a later test be positive, indicating that you are infected with the virus?
This can happen if the patient is tested before the infection develops, i.e. during the incubation period and before any symptoms have appeared. Since the incubation period for coronavirus is 2–14 days it might take some time between transmission of the virus and the onset of symptoms. Negative test results during the incubation period do not rule out that you could be infected, and if you suspect COVID-19 you should get tested again if you develop symptoms of disease.
How do you monitor the spread of COVID-19?
The Public Health Agency uses several different surveillance systems to monitor the spread of COVID-19 in Sweden. Since COVID-19 is subject to mandatory reporting under the Communicable Diseases Act, physicians and laboratories continuously supply data that is analysed by the Public Health Agency every day. Other sources of data are random samples from patients that present to their healthcare provider with symptoms of influenza, or from other groups of people. Statistics from the medical advice service 1177 (web searches and telephone calls) is also used to monitor the situation. The Public Health Agency issues a weekly report showing the number of COVID-19 cases, starting from March 20th 2020.
Collected data provides a background for decisions about interventions that serve to minimise mortality, the number of people affected by the disease, and the negative effects for society. Data from surveillance also makes it possible to monitor and evaluate the effects of interventions so far, and to follow and somewhat predict the further development of the pandemic.