"The R0 value of Omicron's transmission is 7 to 8, and its subtype strain BA.2 reaches the level of 8, which will bring a high risk of infection to the elderly." On March 20, in "New Crown Epidemic Prevention" Zhang Wenhong, director of the National Center for Infectious Diseases Medicine and director of the Department of Infectious Diseases of Huashan Hospital Affiliated to Fudan University, said at the "New Progress Summit Forum 2022 First Quarter" online forum that adequate vaccine protection must be done for the elderly and other vulnerable groups in order to be able to gradually Reopening conditions are critical for Omicron to gradually build up an immune barrier.
What is the R0 value, how to judge the reference value of this index for epidemic prevention and control, and how to help the elderly to establish an immune barrier against the new coronavirus under the situation that the Omicron virus strain is raging?
The basic infection number of Omicron is 2-4 times that of the prototype strain of the new crown
"The R0 value, that is, the basic infection number, means that without external intervention, and at the same time, no one is immune to a certain infectious disease, and no control measures are taken, a person infected with a certain infectious disease will spread the disease. The average number of other individuals infected." Wang Zhiguo, deputy director and chief physician of the Immunization Planning Institute of the Jiangsu Provincial Center for Disease Control and Prevention, told the Science and Technology Daily reporter that if R0<1, the infectious disease will gradually disappear and the epidemic will gradually subside.
If r0=1, the infectious disease will become an endemic epidemic. The larger the r0 index, the stronger the infectivity. The r0 value of 10 is the so-called "one spread to ten, ten spread to one hundred".
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Previous studies have shown that the R0 value of the new coronavirus (prototype strain) is roughly between 2 and 3.2, while the R0 value of the delta + variant strain is about 5 to 8.
The R0 value of the Omicron strain that is currently circulating in the world is 7-8, and its subtype strain BA.2 reaches the level of 8.
"But from the current point of view, this is only an extrapolation value, because many countries have taken measures, and a considerable number of people have been vaccinated. However, from the R0 value, Omicron is aggressive, and its transmission speed is faster. Fast, highly contagious." Wang Zhiguo said that the elderly have relatively low immunity, and most of them have underlying diseases. Once infected, the risk of severe illness and death is higher than that of young people. Therefore, vaccination of the elderly is very important for establishing The immune barrier is crucial.
The elderly and those with underlying medical conditions are most in need of vaccination
From a global set of data, the elderly are even weaker in the face of new coronary pneumonia.
Up to now, the global death toll from new coronary pneumonia has exceeded 6 million. According to the data reported by various countries, the average age is around 70 years old.
According to statistics from the US Centers for Disease Control and Prevention, compared with young people aged 18-29, people aged 65-74 have a 4-fold increased risk of hospitalization and a 65-fold increased risk of death; compared with those aged 75-84 People aged 18-29 had an 8-fold increased risk of hospitalization and a 140-fold increased risk of death; those over 85 had a 12-fold increased risk of hospitalization and a 340-fold increased risk of death.
In contrast, in China, in the Yangzhou epidemic last August, the elderly became the key group of people infected with the virus.
On March 18th, at the press conference on the strict control of epidemic prevention and control held by the State Council Information Office, Zeng Yixin, deputy director of the National Health Commission, said, "There are 1,388 infected people in Yangzhou, among whom there are elderly people over 60 years old. There are 67 severe cases. Because there are many elderly people, the incidence of severe cases is also relatively high. Among the 1388 cases, 38% were vaccinated in the whole process; 65 of the 67 severe cases were not vaccinated or did not complete the whole process of vaccination.”
In the recent Hong Kong epidemic, the mortality rate of vaccinated people was 0.04%, and the mortality rate of those who had not been vaccinated or not fully vaccinated was 1.25%, and 90% of those who died were elderly.
Zeng Yixin pointed out that from the examples of Yangzhou and Hong Kong, it can be seen that first, vaccination has a good protective effect on preventing severe illness and preventing death; second, the elderly and people with underlying diseases are the most in need of protection. Vaccinations are also most needed.
The incidence of adverse reactions of the new crown vaccine is not higher than that of conventional vaccines
As of March 17, among the 264 million people over 60 years old in my country, 211.76 million elderly people have completed the full course of vaccination, which means that there are still 52 million elderly people over 60 years old who have not completed the full course of vaccination, of which the largest proportion For people over the age of 80, only 50.7% of them completed the whole course of vaccination.
Some elderly people are concerned, how is the safety of the vaccine, and will the vaccine aggravate the underlying disease?
Wang Zhiguo said, "At present, according to the reported data, the incidence of adverse reactions of the new crown vaccine is not higher than that of the conventional vaccine."
At present, Jiangsu Province has completed nearly 196 million doses of the new coronavirus vaccine. Some vaccinators have mild reactions such as transient fever, redness, swelling and induration, but generally do not need to take any measures, and they can recover in 1-3 days. At present, the safety of the new coronavirus vaccine in my country is good.
"According to my country's new coronavirus vaccination technical guidelines, elderly people with chronic diseases such as 'hypertension, hyperlipidemia, diabetes' and other chronic diseases, if their health status is stable and the drugs are well controlled, it is recommended to receive the new crown virus vaccine." Wang Zhiguo said.
There are many elderly people who think that they do not often go out of the province and the city, and they will not be infected with the new crown virus only at their doorstep.
In Wang Zhiguo's view, even if you don't travel far, the possibility of contracting the new coronavirus still exists, "For example, vegetable farms, farmers' markets, shopping malls and supermarkets, elderly activity rooms, chess and card rooms, red and white dining places, etc. are places where the elderly gather. These places are often high-risk places for the spread of the disease.”
Wang Zhiguo reminded that I hope everyone will pay more attention to the elderly, mobilize and accompany them to receive the new crown virus vaccine, and jointly build an immune barrier for the health of the elderly.