by Silvia Turin
Today, nearly one in five Chinese would test positive, and the more SARS-CoV-2 circulates, the more likely it is that significant variants with features of greater diffusivity or pathogenicity will emerge
The world health authorities are concerned about the situation of Covid infections in China: The figures are not provided by the government in Beijing, but according to western institutes for health analysis such as the British Airfinity, almost 1 in 5 Chinese would be positive, the intensive care unit was saturated with patients and the number of deaths would exceed 5,000 per day, as reported by Guido Santevecchi (in this article).
Visitors from China arrive
In addition, the now final abandonment of the “zero Covid” policy by China is about to take further, final steps: From the 8 for aircraft and foreign destinations had increased tenfold compared to the previous year.
In addition to concern for the seriously ill in China, there is concern about the epidemiological consequences of such a large number of infections: new, even deadlier variants could emerge that could spread from the Asian country to the rest of the world.
In Lombardy, at Malpensa Airport, travelers arriving from China are already offered an optional swab (and there would be many positives). The measure is used to determine the type of Covid variant of those arriving from the Asian country. Last night – said the General Directorate of Welfare of the region – 210 swabs were taken with relative sequencing.
The danger of the Chinese situation
But why should infections in China be so concerned about the development of new variants? The variants are becoming more likely to emerge as the virus spreads, and in China some forecasts draw two peaks of infection with abnormal numbers: 3.7 million per day in mid-January and 4.2 million per day in March. «RNA viruses like the coronavirus – explains Paolo Bonanni, epidemiologist, full professor of hygiene at the University of Florence – make “errors” called “mutations” with each reproduction. In most cases, the mutations do not lead to major changes in the structure of the virus. Probabilistically, however, the more a virus circulates, the more likely it is that significant variants with features of greater diffusivity or pathogenicity will emerge. It’s like a slot machine: the more attempts are made, the higher the probability of creating a combination that is more widespread or even more aggressive than the virus ».
A poorly immunized population
And this is the World Health Organization (WHO) alert on the situation in China: Due to the “zero Covid” policy, the local population is practically “naive”, that is, they have had almost no exposure to the SARS-CoV virus so far – 2 and has low immunity. In addition, the elderly were rarely vaccinated (only 48 percent of Chinese aged 70-79 and 20 percent of those over 80 received three doses) and the vaccines on offer, Sinopharm and Coronavac, proved to be much less effective than those in Europe and the US be used. Therefore, based on the available estimates, only 25% of the Chinese population would have some immunity to Omicron (vaccine or infection), compared to 84.4% of the population in Italy are vaccinated, without counting those who have recovered.
Beyond Omicron
The virus in China is therefore free to infect millions of people and to replicate and mutate by the millions. But there’s another aspect to consider: the variant that could be spreading might not be Omicron. And that is another reason for concern: “While new variants with different strains (alpha, delta, beta, omicron) emerged in the first two years of the pandemic, only subvariants of omicron have evolved in the last year – explains the epidemiologist – which are a signal of a tendency towards endemization of the virus thanks to vaccines ». The problem today is that with such a high prevalence of the virus, an entirely new variant could actually be born in China, very far removed from the Omicron strain and potentially surpassing the protection offered by the vaccines used to date. “We would then find ourselves in a more dangerous situation that could lead us to a level of serious illness, hospitalization and death that we have not known for some time,” stresses Paolo Bonanni.
Omicron itself, Chinese hospitals demonstrate, is not so mild: «Omicron is no less deadly – confirms Bonanni –. Rather, its aggression was confronted with an immune system trained by vaccination or infection and was therefore reduced in severity”. Even a recent study concludes that had Omicron not encountered a vaccinated population like the western one (or immune to the disease anyway), it would have been just as deadly as the Wuhan strain (but less than the Delta variant).
Vaccination monitoring and recalls
“What we can do today is get immunization boosters (especially for the frail) to prepare for a possible new mode of transmission that could emerge more easily with the millions of infections in China. In fact, it seems very unlikely that the protection afforded by vaccines can be eliminated entirely, while it could decrease proportionately more in those who have not recently recalled,” concludes Bonanni. It is important not to be caught unprepared, both as individuals and as a community: what is happening in China could have happened to us if we had not had effective vaccines. From the tracking point of view, too, the sequencing of positives is essential in order to intercept the entry of new variants in good time.
December 28, 2022 (Modified December 28, 2022 | 1:34 p.m.)
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