In response to Omicron, China's current immune barrier still has two shortcomings: one old and one small.

It is imperative to strengthen vaccination against these two age groups to fill the immunization gap.

  The risk of COVID-19 to the elderly was a scientific fact that was clear from the outset of the pandemic, and globally as well.

Up to now, the number of people who have died from new coronary pneumonia in the world has exceeded 6 million. According to the data reported by various countries, the average age is around 70 years old.

As of 0:00 on March 18, 2022, a total of 5,188 deaths have been reported in Hong Kong, of which 70.5% are over 80 years old, 16.7% are 70-79 years old, and 8.3% are 60-69 years old.

Nearly 90% of them have never been vaccinated, and the mortality rate of vaccinated people is 0.04%. For those who have not been vaccinated or not fully vaccinated, the mortality rate is 1.25%, a difference of 31 times.

  A recent study based on about 1.5 million infected people in the UK also showed that for children aged 0-9, the risk of medical treatment and hospitalization caused by Omicron infection is not lower than that of Delta.

This is also the largest comparative study of Omicron and Delta to date.

  The popularity of Omicron has yet to see an inflection point.

But the known fact is that the full course of the new crown vaccine can effectively reduce the risk of hospitalization, severe illness and death caused by the Omicron variant.

Only 19.7% of people over 80 years old have booster immunization

  "According to the epidemiological characteristics of Omicron, most of them are asymptomatic and mild, and the transmission is more insidious. Even the elderly who do not go out will be infected by their family members. It is also the same infection, and the elderly who have not been vaccinated are at extremely high risk. It's our biggest worry right now," an epidemiologist said.

  The joint prevention and control mechanism of the State Council has always attached great importance to the vaccination of the elderly, and has made deployment arrangements for the vaccination of the elderly many times. Various localities are also actively organizing and coordinating, and taking various measures to increase the vaccination rate of the elderly.

Even so, there are still a considerable number of elderly people who are still in the immunization gap.

  Judging from the data, as of March 17, there were still 52 million elderly people over the age of 60 in China who had not completed the full course of vaccination, and the largest proportion of them were those over the age of 80.

  In terms of different age groups, as of March 17, among the elderly in my country aged 60-69, 70-79, and over 80 years old, the proportion of one-dose vaccination was 88.8%, 86.1%, and 58.8%, respectively, and the whole process was completed. The proportions of basic immunizations were 86.6%, 81.7%, and 50.7%, respectively, and the proportions of completed booster immunizations were 56.4%, 48.4%, and 19.7%, respectively.

  Especially for the whole process of vaccination and booster immunization for the elderly over 80 years old, "this ratio is still relatively low." Zeng Yixin, deputy director of the National Health and Health Commission, once said.

  At the press conference of the Joint Prevention and Control Mechanism of the State Council on March 19, Lei Zhenglong, deputy director of the National Health Commission's Disease Control Bureau and first-level inspector, said, "In the practice of prevention and control, the vaccination of the new crown highlights the need for the elderly. However, judging from the current vaccination situation in various places, there is still room for further improvement in the vaccination rate of the elderly in some areas."

  What does this kind of vaccination short board mean for the elderly?

  According to the statistics of the US Centers for Disease Control and Prevention, compared with young people aged 18-29, the risk of hospitalization for people aged 65-74 increased by 4 times, and the risk of death increased by 65 times; the risk of hospitalization for people aged 75-84 increased by 4 times; The 8-fold increase was associated with 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.

  As you can see from the fifth wave of the epidemic in Hong Kong, you can see the difference between vaccinated and unvaccinated.

According to statistics, as of 0:00 on March 18, 2022, the cumulative number of reported cases was 1,004,313, and the cumulative number of deaths was 5,188, with an overall fatality rate of 0.52%.

Among the deaths, 70.5% were over 80 years old, 16.7% were 70-79 years old, and 8.3% were 60-69 years old.

Nearly 90% of them have never been vaccinated, and the mortality rate of vaccinated people is 0.04%. For those who have not been vaccinated or not fully vaccinated, the mortality rate is 1.25%, a difference of 31 times.

  Therefore, how to make up for this shortcoming has become the most urgent thing at present.

But promoting vaccination of the elderly does not seem to be so easy.

Several Difficulties in Raising the Vaccination Rate of the Elderly

  "We dare not fight. On the one hand, the grassroots do not have the ability to have rich clinical experience. On the other hand, the long-term trust relationship between doctors and patients is relatively weak, and other social conflict mediation mechanisms other than vaccination response compensation are relatively lacking. One thing is worse than one less thing." said a staff member in charge of vaccination at the grassroots level.

  In fact, the adverse reactions after vaccination have indeed brought trouble to the grass-roots vaccination personnel.

"The elderly have many underlying diseases, and many adverse reactions have nothing to do with vaccination, but this is difficult to explain to them, so vaccination is more cautious." Another vaccinator said.

  Since most people over 60 have underlying diseases, they are also at high risk of severe illness and death after contracting the new coronavirus.

Therefore, in the "Technical Guidelines for New Coronavirus Vaccination (First Edition)", detailed regulations are also given for the vaccination of this group, and it is recommended that "chronic disease groups are those who are seriously ill and at high risk of death after infection with the new coronavirus. People with well-controlled chronic diseases are not considered contraindicated groups for new coronavirus vaccination, and vaccination is recommended." For "immune compromised people", it is recommended to receive inactivated vaccines and recombinant subunit vaccines. If adenovirus vector vaccines are used, although the vector virus used is Replication-deficient, but there is no previous safety data for the use of the same type of vaccine, it is recommended to be fully informed and vaccinated after weighing the benefits over the risks.

  For the risk control of the elderly after vaccination, detailed protective measures have also been formulated. "It is required that there must be a doctor in a medical institution above the second level, and a 30-minute observation is required after the vaccination." The person in charge of local disease control said.

  Judging from the existing adverse reaction data after new crown vaccination, there is no difference between the elderly and other different age groups.

  A paper titled "Safety Evaluation of Large-scale Emergency Use of Novel Coronavirus Inactivated Vaccines (Vero Cells)" published by the Chinese Journal of Epidemiology on June 29, 2021, collected 497,743 vaccinations against the new coronavirus, and found that 12~ The 18-year-old population had the highest incidence of adverse reactions, reaching 11.31%, mainly fatigue and pain at the vaccination site.

The second is the population aged 30-39, the incidence of adverse reactions is 1.18%, and the lowest incidence of adverse reactions is the population ≥ 60 years old, the incidence of adverse reactions is 0.32%, and the difference is statistically significant.

  It can be seen that the adverse reactions of vaccination in the elderly population are not as high as those in other age groups.

This conclusion has also been confirmed in other vaccines.

  In the "Expert Consensus on Promoting Seasonal Influenza Vaccination in the Elderly", it was pointed out that in 2017, a foreign systematic review included 7 RCT studies to evaluate the safety of influenza vaccine in the elderly population. The results showed that standard antigen content inactivated vaccine and None of the high antigen content inactivated vaccines reported any vaccine-related deaths, Guillain-Barré syndrome, or anaphylaxis.

An RCT study in the United States that included 9172 subjects aged ≥ 65 years showed that 6.7% and 6.5% of the participants experienced high antigen content inactivated vaccine and standard antigen content inactivated vaccine within 180 days, respectively. Serious adverse events, the difference between the two was not statistically significant.

  Therefore, in terms of safety, it does not constitute an obstacle to the vaccination of the elderly, but in the actual operation process, it is indeed very difficult.

  "The elderly have low willingness to be vaccinated and can be vaccinated at home, but it is still difficult to deal with adverse reactions, especially abnormal reactions. According to the past vaccination requirements, the community will stay for half an hour, and the elderly cannot sit still. Door-to-door service, if everyone has to stay Half an hour, the efficiency is too low. How to solve this problem, the next step should be more sound." A person in charge of local disease control said.

Omicron causes children to be hospitalized at least as risk of infection as Delta

  In addition to the elderly, another shortcoming of the immune barrier is children and adolescents.

  On March 19, at a press conference on Shenzhen's epidemic prevention and control, Lin Hancheng, a second-level inspector of the Shenzhen Municipal Health Commission and a spokesman for the Municipal Epidemic Prevention and Control Headquarters, said that among the people infected with the new coronavirus admitted to Shenzhen recently, Children accounted for 20%.

Among the 20% of cases in children, half were under the age of 6, and the youngest was 1 month old.

It shows that children are generally susceptible to Omicron mutants, which are significantly higher than that of Delta mutants.

  At the press conference of the Joint Prevention and Control Mechanism of the State Council on March 19, Wu Zunyou, chief epidemiologist of the Chinese Center for Disease Control and Prevention, said that people who have not been infected with the new crown virus and who have not received the new crown vaccine are not resistant to the new crown virus. Force, if children and adolescents are infected with the new coronavirus, generally speaking, the symptoms are relatively mild, or they can't feel themselves and feel relatively light, and they are easy to be ignored at this time.

During the epidemic, especially in places where children and adolescents are concentrated, such as schools, symptom monitoring must be strengthened to detect students who may be infected in time, so as to control the epidemic in the bud.

  A recent study based on millions of infected people in the UK also showed that for children aged 0-9, the risk of medical treatment and hospitalization caused by Omicron infection is not lower than that of Delta.

This is also the largest comparative study of Omicron and Delta to date.

  On March 16, The Lancet published a large-scale study from the team of Professor Tommy Nyberg of the University of Cambridge, UK, comparing the severity of infection between Omicron and Delta in people of different ages and immune status, including medical treatment, Changes in hospitalization and risk of death.

  The study collected data on 1,516,702 people infected with the new crown in the UK between November 2021 and January 2022, including 1,067,859 people infected with Omicron and 448,843 people infected with Delta, and found that compared with Delta, Omicron infected people had a 44% lower risk of hospital visits overall, a 59% lower risk of hospitalization within 14 days of infection, and a 69% lower risk of death within 28 days of infection.

  However, this decline is not significant in children aged 0-9 years. The reason may be that, on the one hand, the high transmissibility of Omicron may lead to the increased risk of hospital visits and hospitalization in unvaccinated children; on the other hand, Compared with previous strains, Omicron mainly infects the upper respiratory tract, and children have smaller airways, more severe symptoms, and a higher probability of hospital visits and hospitalizations.

  Several studies conducted early in the COVID-19 pandemic showed that children and adolescents had lower rates than adults.

According to the Centers for Disease Control and Prevention, as the new coronavirus mutates, the rate of infection and symptomatic disease in children and adolescents is comparable to that of adults, and higher than the rate for adults over 50 years of age.

As a result, many countries such as the United States and the United Kingdom have launched new crown vaccinations and booster shots for children and adolescents.

  At present, China has launched the new crown vaccination for children over 3 years old, but no booster vaccination has been launched.

Meanwhile, children under 3 have not yet been vaccinated.

These two factors will increase the risk of infection in children.

  "The antibody level of the new crown vaccine will attenuate 6 months after inoculation, so the protective ability will decrease after 6 months. It is necessary to start the booster injection for children and adolescents over 3 years old. Because of the hidden transmission of Omicron , once the school is infected, it will become an amplifier." The above-mentioned epidemiological expert said.

  In this round of Omicron, school cluster outbreaks have appeared in many places.

  From March 7 to March 15, Beijing reported a total of 43 cases of infection, including 5 primary school students and 4 in Hepingli No. 4 Primary School in Dongcheng District.

  In Lianyungang, Jiangsu Province, on March 4 and 5, 7 infected persons were found to be the same primary school teachers and students, 4 were confirmed cases, and 3 were asymptomatic infections.

  Qingdao Laixi found that 3 students from Laixi No. 7 Middle School were diagnosed on March 4 (fever clinic). From March 4 to 12:00 on March 10, a total of 304 confirmed cases were reported, of which 217 (71.4%) were students and 472 were students. Asymptomatic infections spread to family members after being infected by students.

  The first confirmed case of Jilin Agricultural Science and Technology College appeared on March 6, and 68 new crown infections (20 confirmed and 48 asymptomatic) were found on March 9, and a total of 91 infected people (25 cases) were found on March 11. confirmed, 66 asymptomatic).

  "Not only children and adolescents need to start the booster needle as soon as possible, but also the protection of children under 3 years old to ensure the safety of this group." The above-mentioned epidemiological expert said.

  On March 20, at the "New Crown Epidemic Prevention Summit Forum 2022 First Season" online forum, 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, admitted that in the next anti-epidemic work, if If you do a good job in several aspects, you can win the victory of wisdom in fighting the epidemic.

He believes that the first and foremost is that vaccination must reach a very high level in order to have the conditions for the initial gradual liberalization.

Article author 

Ma Xiaohua

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