Recently, the World Health Organization's official ** published an article titled "Surge in Respiratory Diseases in Children in Northern China" on November 23 this year, which has attracted global attention.
The following day, Maria van Kerkhove, executive director of the World Health Organization's Department of Epidemic Prevention, said in an interview with Stat that the main reason for the current surge in respiratory infections among children in China is the COVID-related immunity gap.
Screenshot of stat** (refer to link 2).
On November 27, the well-known academic journal Nature published an article entitled "What is Behind the Mysterious Wave of Pneumonia in Chinese Children?".". This article attempts to interpret the news released by the World Health Organization a few days ago from a scientific point of view. Author Gemma Conroy argues that the current surge in respiratory infections among children in China is predictable for the same reason that Maria Van Khove has mentioned, namely the "immunity gap" associated with the pandemic, which Conroy calls "immunity debt." At the same time, Conroy pointed to other unusual aspects of the current surge in respiratory infections among children in China.
So, what is "immunity debt"?
During the novel coronavirus pandemic, we have reduced the spread of the virus, reduced the rate of viral infection, delayed the peak of infection, narrowed the scope of infection and controlled the epidemic through non-pharmaceutical interventions (NPIS) such as personal protective measures, environmental measures, social measures and travel measures.
When the pandemic eases, children can continue to implement the following NPIS measures: wearing masks, washing hands frequently, disinfecting surfaces, social distancing, and increasing ventilation. After the implementation of these NPIS measures, people will lack immune stimulation to pathogens, and the susceptible population will increase, leading to a decrease in herd immunity. The difference in the level of herd immunity during this pandemic and before the pandemic is known as immunity debt or immunity gap.
Since the outbreak of the pandemic in 2019, studies have found that strict implementation of the NPIS in the context of vaccination can reduce infection rates, hospitalizations, intensive care unit (ICU) admissions, and deaths. NPIS also has an impact on the incidence of other infectious diseases in children, reducing children's exposure to other pathogens, thereby reducing the incidence of some viral and bacterial infections.
However, due to the decrease in infections, the immune stimulation of the human body by pathogens is insufficient, the susceptible population increases, and the level of herd immunity decreases. After reducing the intensity and scale of NPIS enforcement in many countries and regions, the incidence of infectious diseases such as respiratory syncytial virus (RSV) and bacteria has increased significantly. The longer the pathogen is low, the higher the likelihood of future epidemics of infection and possibly increased incidence of allergic disease.
The green line in the graph represents the incidence of other respiratory infections under normal circumstances, while the red line represents the incidence of other respiratory infections due to the immunity gap caused by the COVID measures. As shown in the chart, COVID measures (such as wearing masks, reducing gatherings, closing schools, etc.) have prevented the spread of other respiratory infections while preventing the pandemic. However, when containment measures are relaxed, some of these suppressed respiratory pathogens are likely to experience a surge in infection. Whether a pathogen will break out due to the "immune gap" after the relaxation of epidemic prevention and control measures depends on its own characteristics.
As ordinary people, we may be more concerned about another important question: does the immunity gap affect an individual's immunity?In other words, if an individual has not been exposed to a pathogen during the pandemic and lacks immunity to it, will they experience more severe symptoms when they are infected again after the outbreak is over?
The answer is no. In the case of RSV, if a child did not have the opportunity to contract it during the pandemic, when they were infected a few years later, the symptoms were still normal: most people would only experience mild symptoms like the common cold, and only a few would need them**.
Although the immunity gap caused by the pandemic will not have a negative impact on subsequent infectious diseases, strict COVID prevention and control measures may have some potential for an individual's immunity in another way
Thanks to strict COVID prevention and control measures, people have reduced their exposure to pathogens, as well as harmless microorganisms in the natural environment. And in the evolution of our immune system, these harmless microbes in the natural environment play a beneficial role. Especially in the early stages of life, exposure to harmless microbes helps our immune system learn to tolerate and avoid unwanted immune reactions, such as allergies and autoimmune diseases. This is known as the "Doctrine of Hygiene" or "The Doctrine of Old Friends".
Therefore, babies born during the pandemic may be at increased risk of developing allergic or autoimmune diseases later in life if they lack access to harmless microorganisms in the natural environment due to pandemic prevention measures.
What should I do?
For responses to the post-COVID spike in respiratory infections, keep the following in mind: first, to prevent a surge in infections, and second, to prevent the surge from straining medical resources.
The World Health Organization (WHO) has provided recommendations for response, including vaccination against influenza, COVID-19 and other respiratory pathogens, as appropriateKeep your distance from the patient;Stay home when you are sick;Undergo inspections and ** if necessary;Wear a mask as appropriate;Ensure good ventilation;Wash your hands regularly.