The inflection point, also known as the inflection point, refers to the point that changes the upward or downward direction of the curve in mathematics. Intuitively speaking, the inflection point is the point where the tangent intersects the curve (that is, the boundary point between the concave arc and the convex arc of a continuous curve). If the function of the graph has a second derivative at the inflection point, the second derivative has a different sign (from positive to negative or from negative to positive) or does not exist at the inflection point.
During the COVID-19 epidemic, it was frequently mentioned by major news media? Epidemic inflection point? Like a word? Will the epidemic inflection point we expect appear? 、? Will the inflection point of the epidemic come within a month? 、? Is there a turning point in the epidemic before the fifteenth day of the first month? Wait a minute.
Where is the turning point of the epidemic?
Turning point refers to the place where the development trend of things in life begins to change. The inflection point of epidemic situation means that the epidemic situation is under control, and the decline in the number of suspected infections and the number of cases is the sign of inflection point.
What are the influencing factors of epidemic inflection point?
All infections have a downward process. The time of decline depends on the immune level of the population and whether the intervention measures taken are effective.
Group immunity is the ability of people to resist the invasion and spread of infectious disease pathogens, which is reflected in the proportion of people with immunity to the total population.
Academician Wen believes that the improvement of group immunity is the most important factor in this turning point.
Therefore, infected people are found early and isolated early; The medical team developed the vaccine in novel coronavirus, and strengthened contact tracking and quarantine isolation; People wear masks, try to avoid contact with others, work and rest regularly, and enhance their own resistance. These measures can promote the inflection point to appear as soon as possible.
How to get the time when the epidemic inflection point appears?
According to the epidemiological model, the inflection point can be found. By establishing a mathematical model to fit the cumulative incidence data in COVID-19, we can infer the incidence peak, duration and cumulative incidence number, draw the epidemic curve and grasp the epidemic situation.
However, the analysis and prediction in the model need certain preconditions, such as the possibility of infection between people is not much different, the transmission route is easy to realize, and the comprehensive prevention index is relatively unchanged. Any change in these preconditions will affect the change of epidemic peak and epidemic situation.
At present, many research teams from Lancaster University, Johns Hopkins University, Hong Kong University and other universities have assessed and predicted the transmission path and speed of the virus through modeling, so as to better grasp the influence and epidemic characteristics of novel coronavirus.
In fact, any model is just a tool for analysis and prediction. It is based on the existing data and information, and its conclusion may be relatively accurate, even accurate, which has important reference significance for people to judge the epidemic trend and make decisions. However, we must also understand that all forecasting models have limitations, and we still cannot predict the exact date of the inflection point of the epidemic. The importance of epidemic inflection point to individuals may be limited, but it is still very important for epidemic prevention decision-making and deployment. According to experts, although right? Turning point? It can't be predicted accurately, but it won't wait long.