It has been more than two and a half years since the COVID-19 pandemic! In the past two years, both our country and the entire world have been affected by the new crown epidemic. In the past two years, human weapons to fight new crown are also being continuously developed. The new crown treatment drugs that have been launched, and the new crown vaccine are all our strong guarantees for us to fight the new crown epidemic.
Just recently, Hainan Boao Lecheng Pilot Zone introduced a new drug that was urgently authorized in Europe and the United States last month. This drug is not a treatment for the new coronavirus infection, but a drug used to prevent the new coronavirus infection. It is reported that there are two injections of this drug, with a cost of 13,300 yuan, and nearly 100 people have been injected with this drug. Many friends may wonder, what is the difference between such expensive drugs and free vaccines that can also prevent COVID-19 infection? Who is more suitable for using such drugs? Today, let’s take a look at this newly launched COVID-19 prevention drug.
What is the difference between the new crown preventive drugs and the new crown vaccine?
The new crown prevention drug launched this time is called " Enshide " (Evusheld). In terms of drug classification, it belongs to a monoclonal antibody drug. This drug is composed of two bottles of injections, each bottle contains a different monoclonal antibody. It can be said that it is a monoclonal antibody combination drug, which contains two monoclonal antibodies, tixagevimab and cilgavimab. Both antibodies are antibodies isolated from B cells of patients infected with the new coronavirus. At the same time, it has undergone a prolonged half-life modification, reducing the binding to the Fc receptor and complement components, thereby increasing the retention time of this antibody after entering the human body (equivalent to the half-life of the drug).
From the perspective of mechanism of action, exogenously input antibodies with anti-coronavirus infection to the human body can enhance the body's immune system's ability to fight against the new coronavirus. For people who have been infected, if there are a large number of new coronavirus antibodies in the body, it also plays an important role in preventing severe risks.
No matter what, the effect of this drug seems to be similar to that of the new crown vaccine. We inject the new crown vaccine is also to produce antibodies, strengthen our resistance to the new crown virus, and reduce the risk of severe illness. What is the difference between the two? Simply put, the difference between the new crown preventive drugs and the new crown vaccine lies in the difference between "passive" and "active".
The function of the new crown vaccine is to stimulate the body to produce an immune response through injecting the vaccine, and then produce antibodies, thereby enhancing the body's immunity against the new crown, which belongs to "active immunity"; while the new crown preventive drug is a drug that directly injects the isolated antibodies into the human body to play a role, which belongs to " passive immunity ". To give an inappropriate example, for a person to improve poverty, the COVID-19 vaccine is equivalent to the inducement of opinions that stimulate him to work hard to make money; while the COVID-19 prevention medicine is equivalent to giving him a sum of money directly.
COVID-19 prevention drugs cannot replace vaccines, and it is not an extravagant
Compared with COVID-19 vaccines, COVID-19 prevention drugs are more technically difficult, and their cost and price are higher. It is impossible to become a substitute for COVID-19 vaccines. Moreover, compared with COVID-19 prevention drugs, COVID-19 vaccines can stimulate the human body's natural antibodies to the new coronavirus, and the types of antibodies are also richer. For people with normal immune functions, regular injection of COVID-19 vaccines to maintain their immunity to the new coronavirus is a good way. There is no need to use additional monoclonal antibody drugs to prevent COVID-19.
But it is undeniable that some people with low immunity produce relatively weak antibodies after being vaccinated, and sometimes they are not enough to resist COVID-19 infection, and the risk of severe illness is also higher. In addition, the following related physical health problems, such as immunosuppression problems or patients undergoing immunosuppression treatment are not suitable for COVID-19 vaccines. For friends who have these conditions, using monoclonal antibodies to COVID-19 prevention drugs is a good and beneficial supplement, which can reduce the risk of COVID-19 infection and the risk of developing severe illness after infection.
Therefore, if this new crown prevention drug is more suitable for whom, not everyone actually needs such a drug. Only those with low immunity and high risk of severe illness, as well as those who are not suitable for vaccination with the new crown vaccine are more suitable for using this drug. Can this drug
effectively prevent Omickron variant infection? More clinical practice is still needed.
In terms of mechanism of action, Tixagevimab and cilgavimab bind to different and non-overlapping epitopes of the spike protein receptor binding domain of the new coronavirus, thereby effectively neutralizing the virus. Its half-life in the human body can be as long as 90 days. In theory, it can effectively reduce the risk of new coronavirus infection and severe disease after infection within 6 months after injection.
According to the official website of the drug developer, the detailed results of the PROVENT Phase III pre-exposure prevention (prevention) trial show that Evusheld (tixagevimab and cilgavimab) reduces the risk of symptomatic COVID-19 infection by 77% in the preliminary analysis and 83% in the preliminary analysis. Six-month follow-up analysis compared to placebo. During the six-month follow-up, there were no serious illness or deaths related to COVID-19. Data like
all seem very gratifying, but if we look carefully at the research results paper published in the New England Journal of Medicine, we will find that such data is actually lacking. A total of 5,197 participants received randomization, of which 3,461 participants received Evusheld injection, while 1,736 participants received placebo, while only 8 of the medication group had symptomatic COVID-19 infection, while 17 of the participants in the placebo group had symptomatic COVID-19 infection. Therefore, although the number of participants was large, the relative risks brought by this drug were reduced, the real data was actually very limited.
In addition, the author also mentioned in the discussion part of the article: "In February 1022, due to the emergence of the BA.1 subvariant, FDA recommends increasing the dose of Evusheld to 600 mg; the suggestion for repeated dosing intervals has not been confirmed, waiting for further data ”. Compared with the BA.1 variant, the currently popular BA.4 and BA.5 have stronger immune escape. Therefore, whether the efficacy of this drug in preventing the new Omickron variant is required to increase the dose. The economic burden caused by increasing the dose also needs to be confirmed and considered during the further medication process.
