Delta mutant strain is still protected by existing vaccines
The global epidemic is still in a pandemic state, with peaks of epidemics appearing in many countries.
On the 31st, at a press conference held by the State Council's Joint Prevention and Control Mechanism, the spokesperson of the National Health Commission Mi Feng revealed: Since July, the country has added 27 newly imported confirmed cases every day, and the pressure on foreign defense imports has continued to increase; A total of 328 new local confirmed cases have been reported across the country, which is close to the total of the previous five months. 14 provinces have reported new local confirmed cases or asymptomatic infections.
In the recent outbreak of a local cluster in Nanjing, many related cases have been found across the country. Compared with previous epidemics, what are the characteristics of the Nanjing epidemic?
Is there a risk of spreading to other regions?
What measures will be introduced at the national level to control the delta mutant strain that caused the epidemic and its characteristics of spreading in many places?
In response to many public concerns, He Qinghua, first-level inspector of the National Health Commission for Disease Control, Guo Yanhong, inspector of the Medical Administration and Hospital Administration, Feng Zijian, researcher of the China Centers for Disease Control and Prevention, Wang Huaqing, chief expert of the immunization program, and members of the expert group of vaccine research and development of the scientific research team Shao Yiming responded.
Delta virus has increased infectivity and high pathogenicity, and the new crown vaccine has reduced its protection but still has a preventive effect
Since the local case was reported in Nanjing on July 20, as of 24:00 on the 30th, a total of 262 cases related to the epidemic have been reported.
According to He Qinghua: The epidemic was caused by the import of the delta mutant strain; it is currently summer vacation, where people gather in tourist resorts; the place where the population is dense, and it is an international airport with a relatively large flow of people, so there will still be continued transfers in the short term. The risk of proliferation in other regions.
Feng Zijian further explained that the epidemic was first imported through Nanjing Lukou Airport and caused further spread. There were cases and infected persons in many provinces.
Since the spread occurs in densely populated places with a large number of floating populations, the risk of spread of the epidemic is high and it is difficult to control.
At present, in addition to strong comprehensive measures for epidemic control in Nanjing and Zhangjiajie, a series of control measures including large-scale investigation and tracking of people flowing out of the two places have been urgently initiated nationwide.
Feng Zijian said that in the recent period, various countries, including the WHO, have strengthened research on the characteristics of Delta virus. Based on current research, the Delta strain shows three very obvious characteristics: First, the transmission capacity has been significantly enhanced.
According to the WHO study, Delta virus has increased its transmission rate by nearly 100% compared with other virus strains.
At the same time, its incubation period and passage interval have been shortened by an average of 1 to 2 days.
Therefore, if there is no strong prevention and control measures to intervene, and vaccination to prevent the spread, the epidemic will multiply at a very significant speed, and the prevention and control will become more difficult.
The second is to increase the severity of the disease.
He said that in the research and observation of the epidemic situation in Guangdong, my country, it has not been seen that it can significantly increase the severity of the disease.
However, in a study in the United Kingdom, it was found that the severity of the disease in patients with Delta virus showed signs of increasing.
Compared with the alpha variant, the risk of hospitalization for patients infected with the delta variant was increased by 2.6 times.
As for its impact on the fatality rate, no clear research results have yet been obtained.
Third, existing research and observations suggest that the new crown vaccine may have a reduced protection against delta virus, but the current vaccine still has a good preventive and protective effect on delta virus.
Why do I still get infected after being vaccinated with the new crown vaccine? Do I need a booster shot?
According to Wang Huaqing, the new crown virus continues to mutate, and the WHO has listed four mutated strains as "virus strains of concern", among which is the Delta strain.
According to WHO statistics, Delta virus strains have been detected in 132 countries, and some countries have detected more than 80% of the strains.
He specifically reminded that in addition to good vaccination, for individuals, they should still wear masks, do good hand hygiene and frequent ventilation, and maintain a social distance of more than one meter in public places.
Why do I still get infected after being vaccinated with the new crown vaccine?
How protective are the vaccines of various technical routes around the world against the new crown variant?
In response to this question, Shao Yiming introduced that from the current global situation, being infected again after being vaccinated is called a breakthrough case. It is a normal state, and it is not an exception.
However, it needs to be emphasized that breakthrough cases are still a small number of people who have received more than 3 billion doses of vaccine in the world.
Shao Yiming explained that the new coronavirus vaccine was used in humans for the first time, so many are still in the process of data accumulation.
Clinical data shows that no vaccine can prevent infection 100%.
Existing studies have also shown that vaccines of various technical routes around the world have indeed shown a certain degree of decline in the protection of the new crown variant strain, but this variant strain is still within the scope of vaccine protection.
According to public information, some countries in the world have clearly provided people with new coronavirus vaccine booster vaccination.
In response, Shao Yiming pointed out that more than 3 billion new crown vaccines have been vaccinated globally.
In order to better respond to the epidemic prevention and control, many countries are considering intensified vaccination.
At present, after all vaccines are vaccinated, the antibody level will decrease over time, but the immune memory still exists. Therefore, once the virus is infected, a strong memory response is stimulated within a week, and the antibody will rise substantially.
There is not enough evidence to show that a third dose of vaccination is needed for the entire population.
He said that for the elderly who have completed immunization for more than 6 to 12 months and have weak immune functions and patients with underlying diseases, as well as those who have to work in high-risk areas due to work needs, those who are engaged in high-exposure-risk occupations in China The population, whether it is necessary to carry out intensified injections, and when to carry out intensified injections, is currently being studied.
The mode of transmission has not changed, and the control measures need to be stricter and more serious
Compared with the old strain, has the delta virus transmission mode changed?
Are the various prevention and control measures taken in the past against old strains and other mutant strains still effective?
Feng Zijian made it clear that although the transmission capacity of this virus has been significantly enhanced, its mode of transmission has not changed, and it is still spread through respiratory droplets and exposure to pollutants.
In addition, this virus can also be transmitted through the air under certain conditions, or called aerosol transmission, especially indoors in small and poorly ventilated spaces.
Therefore, the various prevention and control measures taken in the past against old strains and other mutant strains are still effective.
However, due to its increasing infectivity, the control measures taken to block the epidemic must be stricter, more rigorous, and more serious.
It's the peak summer travel season, can you still go out to play?
How to strengthen protection is everyone's biggest concern.
In this regard, Feng Zijian said that there are several important points regarding the prevention and control of the epidemic during this period: first, people in high-risk areas of the epidemic should cancel their outings; second, people in other areas should carefully check the epidemic risk of their travel destinations before traveling. State, postpone traveling to high- and medium-risk areas; third, no matter where you travel, personal precautions must be taken, including wearing masks, washing hands frequently, and avoiding and reducing indoor crowded places as much as possible.
In outdoor activities, you should also pay attention to maintaining proper interpersonal distance; fourthly, elderly people, patients with chronic diseases, especially those who have not completed the full course of COVID-19 vaccination or have received the full course of COVID-19 vaccination but have not yet reached 14 days, should try not to go Travel outside.
(Beijing, July 31st, by our reporter Jin Zhenya)