August 8, 2022

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What is “breakthrough infection” of COVID-19 and related countermeasures?

What is “breakthrough infection” of COVID-19 and related countermeasures?

What is “breakthrough infection” of COVID-19 and related countermeasures? Recently, as the delta strain of the highly infectious mutation virus of COVID-19 has accelerated globally, some countries have reported that the number of “breakthrough infection” cases of COVID-19 vaccination is on the increase. What is “breakthrough infection”? What impact will it have on the protective efficacy of the vaccine?

“breakthrough infection” reported in multiple countries

“Breakthrough infection” refers to a pathogen breaking through the defense line of the vaccine, causing the person who has completed the vaccination to be infected with the disease that the vaccine should prevent.

This is because the protective efficacy of all vaccines is difficult to reach 100%. The lower the protective efficacy, the higher the incidence of “breakthrough infection”. Even with the most effective vaccines, individual differences can lead to “breakthrough infections” in individuals with low immune responses.

Recently, some countries with high vaccination rates have reported multiple cases of “breakthrough infection”. The latest statistics from the Centers for Disease Control and Prevention of the United States show that as of July 26, the United States has reported a total of 6,587 cases of “breakthrough infection” who were hospitalized or died after vaccination, of which 74% were patients 65 years of age and older, and a total of 1,263 cases were reported. Death.

The elderly and those with basic diseases are still high-risk groups that develop into severe illness or even death after ‘breakthrough infection. 

The Israeli Ministry of Health reported on July 24 that a total of 5770 cases of “breakthrough infection” after vaccination have been discovered in the country, of which 495 are receiving hospitalization and 123 have died. A recent study published in the New England Journal of Medicine showed that of the 1,497 Israeli medical workers who were fully vaccinated with Pfizer, 39 had “breakthrough infections”.

What is "breakthrough infection" of COVID-19 and related countermeasures?

Challenge the vaccine effect

Many viruses mutate quickly, escape existing vaccines, and cause “breakthrough infection.” In the history of global vaccines, “breakthrough infections” have occurred from time to time, and the more typical ones are “breakthrough infections” after influenza and hepatitis B vaccination caused by virus mutations.

Variant strains of COVID-19, including the Delta strain, are challenging the effectiveness of vaccine protection. Zhang Jun said that “breakthrough infections” caused by the Delta strain are more common, although it is still uncertain whether the vaccine has weaker protection against the strain than the prototype strain, or the strain itself is more infectious and more efficient in transmission. However, the neutralizing activity of serum antibodies against certain strains of various vaccines currently on the market is indeed weakened after immunization.

According to data released by the Israeli Ministry of Health on July 22, due to the delta strain, the effective rate of Pfizer’s COVID-19 vaccine in Israel to prevent COVID-19 infections has dropped to 39%.

However, “breakthrough infection” does not mean that the vaccine is completely ineffective.  In research reports with strong data science, the effectiveness of various vaccines in preventing death and severe illness is significantly higher than that in preventing mild illness or infection, but there are still severe illnesses and deaths caused by “breakthrough infection”. happen.

How to deal with the epidemic

In the face of the continuous mutation of the new coronavirus and the increasing trend of “breakthrough infection” cases, many countries have adopted methods such as establishing a “breakthrough infection” case database and carrying out enhanced vaccination.

For example, the US Centers for Disease Control and Prevention has established a vaccine “breakthrough infection” database, covering patient demographic information, geographic location, vaccination time, vaccine type, and virus sequence of infections and other detailed information. Local disease control agencies can report and query the information on “breakthrough infection” cases recorded in the database.

The emergence of “breakthrough infection” cases may mean that we have to accept the long-term coexistence of the new coronavirus. “We need to learn how to coexist with the virus and minimize the impact of the virus on daily life.” said Paul Griffin, an associate professor at the University of Queensland in Australia and an expert in infectious diseases and microbiology. He believes that in response to “breakthrough infection”, on the one hand, we must continue to increase the vaccination coverage rate, on the other hand, we should also continue to maintain social distancing, wear masks, and high detection rates.

Some experts also suggested that in order to deal with “breakthrough infection”, we can speed up the development of more protective vaccine formulations, appropriately increase the number of vaccine immunization doses, namely booster injections, and adopt new immune enhancement technologies.

From the perspective of increasing the comprehensiveness of vaccine immunization mobilization, the current large-scale intramuscular injection of the COVID-19 vaccine mainly mobilizes the systemic immune response, but does not have the effect of local respiratory tract immune mobilization. Therefore, it can strengthen the research and mobilization of respiratory tract immune vaccines. Exploration of combined use with intramuscular vaccines.

(source:internet, reference only)


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