The incubation period refers to the length of time that elapses from the moment of infection with a causative agent (for example, a bacterium) until the onset of the first symptoms. The length of time it takes for the virus to develop into an infectious disease is considered to play a key role in resisting the spread of the virus. The shorter the incubation period, the faster someone becomes infected and the outbreak spreads faster, leaving very little time to detect the virus and delay the spread.
At the onset of the epidemic the incubation period (from exposure to the onset of clinical symptoms) the average of the virus was 6 days, with a range of 2 to 11 days. Since then it has started to shrink – in the alpha strain it has lasted about five days and about four days in the delta strain. Preliminary findings based on thousands of patient reports now show that the omicron may have further reduced the incubation period to three days.
Epidemiologists around the world point out that we are only a few weeks into our fight against omicron, and it is not easy to gather data on incubation periods, which may vary between populations, or understand exactly how the virus gets along with our cells, but the early warning signs are here.
Are antigen tests relevant to Omicron?
A mass infection case in Oslo can provide preliminary information on the intensity and speed of infection of the omicron. Of the 111 participants in the Christmas party, 73% (80 people) were subsequently diagnosed with SARS-CoV-2. Of these, 17 with the Omicron variant. The analysis of additional samples is ongoing, and it is assumed that most sick people are infected with the Omicron variant.
A preliminary study that traces the findings of the Oslo outbreak reveals that the symptoms appeared quickly – usually within about three days. What is even more disturbing is that almost every person who was reported to have been infected with Omicron said he was vaccinated, and received a negative result of an antigen test sometime in the two days before the party. This again shows that the bacterium is spreading among people so vigorously that the quick test results have quickly become obsolete.