A week ago, 10 million people worldwide were diagnosed with new coronary pneumonia, and many countries are still in the midst of the first pandemic, and the number of confirmed cases continues to climb. And when the outbreak began to sweep the globe, the most controversial “group immunization” policy seemed to have had little effect today. Can group immunity be achieved? I’m afraid not, says a study published today in The Lancet.
Researchers from the Carlos III Institute of Health in Spain conducted a national epidemiological study in Spain with more than 60,000 participants. They found that the Seroanti-positive rate in Spain was only 5%! Even in the vicinity of Madrid, where the positive rate is high, it is only a little more than 10%, the lowest in coastal areas, or less than 3%, and at least one-third of the serotopositive-positive population is asymptomatic.
Although some serological testing studies on the new coronavirus have been published before, these studies are generally relatively small, or take medical staff as samples, did not conduct random sampling, and did not reflect the serum antibody-positive rate of the general population.
As a result, researchers in Spain conducted the study, which included 61,075 people, covering different genders, ages and areas of residence, after a two-stage sample of the population was excluded from the problem and who were unwilling to participate in the study and other people with various conditions.
Serum antibody detection has two: instant detection of fingertip blood and immunotherapy of chemically luminescent particles after venous puncture, which mainly detectig igG antibodies, which last longer than IgA and IgM.
Between 27 April and 11 May, the sample of all participants in the sample received an instant test of 5.0% serotoon positive and the immunoassay positive rate of 4.6%.
The differences between regions are clear, with more than 10 per cent of tests tested in seven regions of central Spain, including Madrid, while in coastal areas, where with the exception of Barcelona, which exceeds 5 per cent, almost none of them are more than 3 per cent. The more large cities, densely populated, the higher the positive rate, the more than 100,000 inhabitants of the town, the positive rate of 6.4%, while the less than 5000 residents of the positive rate of only 2%.
Seroantibody positive rates for instant detection (above) and immunoassay (below) in different regions of Spain
According to age stratification, the positive rate is 1.1% for infants under one year of age, 3.1% for children aged 5-9 years, and the positive rate increases with age, reaching a maximum of 6% at 45 years of age and above, which can be maintained around 85 years of age and over 85 years of age, with a sharp decrease in the positive rate.
Seropositive rate varies with age
In addition, there was no significant difference in the positive rate among different genders.
Of the participants who tested positive for serum antibodies, 32.7 percent and 28.5 percent of the participants were asymptomatic, and combined with the overall positive rate, the researchers estimated that in Spain, there would be about 376,000 to 1042,000 asymptomatic infections.
For participants who experienced new coronary-related symptoms, both tests had a positive rate of 16.9 percent. In the participants who tested positive for nucleic acid 14 days ago, the serum antibody positive rate was as high as 88.6%-90.1%, while the participants’ positive rate was only 45.6% in 14 days.
This is the largest known new coronary virus serological study in the European population. Spain is one of the countries most affected by the new crown in Europe, with more than 290,000 people diagnosed and more than 28,000 deaths, compared with more than 40 million in Spain. At such a high rate of diagnosis, the antibody-positive rate is only 5%, far from the requirement of at least 60% of the population immunity requirements.
The results of this study were similar to those conducted in a small-scale, 1,000-person study in Geneva, Switzerland, when participants in Geneva had a sero-to-antibody positive rate of 10.8 per cent, and earlier, the same was true of studies conducted by researchers in China, which showed a positive rate of only 3.8 per cent in the high-exposure population about 4-8 weeks after the peak of infection in Wuhan.
Based on these findings, an op-ed published in the Lancet at the same time suggests that group immunity through uncontrolled natural infections is not only immoral, but simply impossible, and that a second pandemic is likely to occur quickly if controls are removed.
So, although the weather is getting hotter and hotter, we go out or wear a good mask, do a good precaution, do not mind