The outbreak of the XBB strain in New York State this week has caused many netizens to wonder whether the spread of the XBB strain to the country will cause severe secondary infections of and . I have carefully studied the recent secondary infection data in New York State in the United States and will give you a detailed introduction.
Since the state of New York in the United States began to register new crown secondary infection cases in January 2021, as of the end of December 2022, a total of 515,400 cases of secondary infection have been recorded, while New York State has recorded a total of 6.93 million positive infections so far. Therefore, the recorded rate of secondary infection with COVID-19 is 7.4%.
The definition of secondary infection in the United States is two positive cases of COVID-19 for more than 90 days, so the longer the time, the higher the proportion of secondary infections recorded. From January 2021 to December 2022, has experienced a total of 24 months , as well as several rounds of new mutant strains, so 7.4% does not seem to be a very exaggerated figure. What do you think?
Let's take a detailed look at the time distribution of the more than 500,000 new crown secondary infections in New York State in the past 24 months.:
1. During January-November 2021, the number of secondary infected patients was very small;
2, Almost all secondary patients occurred between December 2021 and December 2022! !
What does this mean?
We all know that in December 2021, a Omicron pandemic began to occur in the United States, which means that the Omicron strain can more significantly escape the immunity of previous new coronavirus strains and vaccines , resulting in significant secondary infections.
For a clearer argument, we first find the popular strain data in New York State in the United States from December 2021 to December 2022: From the figure below, we can see that a total of 5 waves of major mutant strain switching occurred continuously during this period: BA.1, BA.2, BA.4/5, BQ and XBB.
We focused on the secondary infection data segment in New York State in the past 12 months. We can see that each peak of secondary infection almost corresponds to the epidemic caused by the switching of five major Omicron mutant strains, including BA.1, BA.2, BA.4/5, BQ and XBB.
However, fortunately, after the BA.1 strain caused a significant wave of secondary infections in December 2021, the secondary infections caused by the BA.2, BA.4/5 and BQ strains have dropped significantly, only about 20% of the BA.1 peak period.
However, we can also observe from the figure that the number of secondary infections caused by XBB in December 2022 is about 50% higher than the number of secondary infections caused by BQ !
Let’s make a rough estimate using the secondary infections during the XBB outbreak in New York State:
The current XBB outbreak in New York State, USA, occurred approximately 90 days after the BA.5 epidemic, and during this period, the number of secondary infections per week was around 14,000. Therefore, if the secondary infection rate does not change significantly in the next three months (we can see that the secondary infection rate due to Omicron infection in New York State has remained almost stable in the past six months), the cumulative number of secondary infections will be approximately 170,000, which means the proportion of secondary infections is 2.4%; In the next 6 months, the cumulative number of secondary infections will be approximately 350,000, which means the proportion of secondary infections is 5%.
Of course, secondary infection is related to many factors, such as the level of antibodies caused by the previous infection, vaccination level, season, etc. Therefore, the current extent of secondary infection caused by XBB, especially the probability of secondary infection faced by BA.4/5 infected patients, still needs to be observed in the future. Detailed statistical data. However, judging from the overall performance of the Omicron strain in the past six months, I also tend to believe that the proportion of secondary XBB infections in my country in the next nine months will not be higher than 5%. Of course, for our one billion infected people at one time, 5% is not a small number.
Do you think my judgment is reasonable?
References
COVID-19 data for New York | Department of Health (ny.gov): https://coronavirus.health.ny.gov/covid-19-data-new-york
COVID-19 variant data | Department of Health (ny.gov): https://coronavirus.health.ny.gov/covid-19-variant-data
outbreak.info SARS-CoV-2 data explorer: https://outbreak.info/location-reports?xmin=2022-10-02&xmax=2023-01-02&loc=USA_US-NY&pango=B.1.617.2&selected=B.1.617.2
