The second study, the Sisonke Study, assessed the effectiveness of the Johnson & Johnson vaccine. Here, too, the rate of those who tested positive during Omikron increased compared to the beta and delta waves. During Omikron, 16 percent of the samples were positive and asymptomatic, with the previous variants it was 2.6 percent. These data come from the first three weeks of December 2021.
The researchers assume that the asymptomatic courses contribute significantly to the spread of Omikron, since infected people do not notice their infection and thus pass it on to others. They write that the “higher asymptomatic transmission rate is likely an important factor in the rapid spread of the variant, even in populations with high prior coronavirus infection rates”.
In South Africa, despite strict lockdown regulations, many were infected with SARS-CoV-2 earlier. In Gauteng, where reports about Omikron surfaced for the first time, the recovery rate was 72 percent even before the new variant. This and the fact that the South African population is on average significantly younger make comparisons with Europe difficult.
A recently published meta-study shows that in Europe 44 percent of those infected have no symptoms, in North America the figure is around 46 percent and in Asia 28 percent. The results underline the importance of regular testing so that asymptomatic people can isolate themselves during the infection and prevent the virus from being passed on. Other measures such as wearing FFP2 masks, keeping your distance or simply washing your hands are also important to make transmission by asymptomatically infected people less likely.
Omikron is passed on more quickly
Another reason for the rapid spread of the Omikron variant was provided by the health economist Thomas Czypionka from the Institute for Advanced Studies (IHS) in conversation with the Austria Press Agency.
The fact that Omikron is spreading so rapidly is due to the immune escape, primarily due to the shorter serial interval between two infections. In other words: An infected person can pass the virus on more quickly than with Delta, for example, because they become infectious more quickly after being infected.