Pfizer Announced A Breakthrough In Mrna Technology With 95% Final Effective Rate Of New Crown Vaccine

On November 18, local time, good news came again from the new crown vaccine jointly developed by German biotechnology company (biontech) and Pfizer Pharmaceutical Co., Ltd. in the United States. The final data of phase III clinical trials showed that the effectiveness of the vaccine reached 95%, and the effective rate in adults over 65 years old was more than 94%. Earlier, the two companies announced on November 9 that interim analysis data showed that the vaccine was more than 90% effective.

Pfizer decided to seek emergency authorization from the U.S. Food and drug administration within a few days. If the emergency authorization is approved, it is expected to start selling the vaccine by the end of the year and inject it into a part of the population.

In addition, Moderna, a US biotech company, announced on November 16 that its vaccine effectiveness reached 94.5% according to interim analysis data.

Safety and effectiveness are the two major criteria for the successful marketing of vaccines. While the effectiveness data of the two vaccines are encouraging, how about their safety? How to solve the problems of vaccine transportation and refrigeration? The 21st century business reporter recently interviewed Huang Huang Huang, PhD, immunology, Stanford University School of medicine.

Both effectiveness and safety data should be concerned

At present, the vaccine efficacy data developed by Pfizer, biontech and Moderna are the most reported and concerned by various media. Both vaccines require two injections.

How did the data come from? Huang Huang told the 21st century economic report that the third-party specialized agencies are responsible for data management and collection in the process of clinical trials of vaccines and pharmaceuticals, not by pharmaceutical companies themselves. Therefore, the 90% effectiveness data released by Pfizer last week and 94.5% effectiveness data released by Modena this week belong to interim analysis of phase III clinical data.

Pfizer and biontech said that in the trial of nearly 44000 adult volunteers, 170 subjects were infected with the new coronavirus and developed at least one symptom, of which 162 were from the placebo group (i.e. receiving the placebo) and 8 from the vaccine group (i.e., vaccinated). Among them, 95 volunteers from the placebo group participated in the trial.

Pfizer and Modena both said they would continue to collect safety tracking and effectiveness data. According to the prescribed process, both companies will analyze the data comprehensively, compile them into documents, and then seek emergency authorization from FDA.

Pfizer and biontech said they had collected safety data for about 19000 subjects over a two-month period as required by the FDA, but are still evaluating the results. Modner said the results would be submitted to regulators when the final analysis of 151 cases and two months of safety data tracking were completed.

Comparison of severe cases, side effects and applicable age groups

So, how should we look at the data of 94.5% and 95% validity? Does it mean that a vaccine is better?

First, how to understand validity data? In short, it refers to the probability of infection with the new coronavirus after vaccination, so as to judge the degree of protection of the vaccine to the human body. Take the 94.5% effectiveness figure of Modena as an example. The published data is that of the 95 confirmed patients, 5 are from the vaccine group and 90 are from the placebo group, which means that the probability of new coronavirus infection after vaccination is reduced to 5%.

Therefore, Huang Huang pointed out that in essence, there is no big difference between the two. It can not be simply said that the vaccine with 95% effectiveness is better than 94.5% vaccine.

Secondly, the judgment of data also needs "symmetry". To judge whether a vaccine is effective, in addition to the statistical data of effectiveness, other further indicators are needed, including the number of serious cases, the reported side effects, and the applicable age group.

The number of severe cases is to determine whether the vaccine has the ability to prevent severe symptoms. According to the clinical trial data of Pfizer and biontech, there are 10 severe cases in 170 confirmed cases, including 9 cases in the placebo group and 1 case in the vaccine group; according to Modena's data, there are 11 serious cases in the placebo group among the 95 confirmed cases.

In terms of side effects, most adverse events of Modena were mild or moderate. Grade 3 events (severe) with a frequency greater than or equal to 2% after the first administration included injection site pain (2.7%), side effects after the second dose included fatigue (9.7%), myalgia (8.9%), arthralgia (5.2%), headache (4.5%), pain (4.1%) and erythema / redness at the injection site (2.0%). These adverse events are usually transient.

Pfizer said in its latest report that serious side effects included fatigue (3.8%) and headache (2%), and fewer and lighter adverse events were reported in the elderly after vaccination. Pfizer did not report any side effects in the interim analysis.

In terms of applicable age groups, Pfizer's latest data show that 41% of participants are between 56 and 85 years old, and the vaccine's effective rate for adults over 65 years old is more than 94%. Modner pointed out that among the 95 confirmed patients, 15 were over 65 years old.

Judging from the degree of side effects mentioned above, Huang Huang pointed out that there is no need to worry about short-term safety data at present, because the verification of safety belongs to the phase II clinical trial to be completed. However, in the long run, if a wider range of injections is carried out in the future, the safety monitoring needs to be continuously observed.

From "1" to "1"

Huang Huang pointed out that once Pfizer and Modena's vaccines were approved by FDA, there would be many positive implications for the future development of vaccines.

First of all, this kind of mRNA based vaccine route will be proved to be effective, which is also the most important enlightenment in vaccine development. Huang Huang believes that this is a qualitative change from 0 to 1. Previously, although many biological enterprises in the United States are trying to use mRNA based vaccines, most of them are still in the phase I and phase II clinical trials. The outbreak of the black swan event, Xinguan epidemic, and the government's efforts in promoting policies and funds have accelerated the progress of this vaccine route.

For example, Modena received $955 million from the U.S. government to develop its vaccine, which also agreed to pay up to $1.53 billion for the vaccine. Pfizer has signed a supply agreement with the United States worth nearly $2 billion.

Secondly, it provides new ideas for the research and development of vaccines for other diseases, because its advantages are also reflected in the development of vaccines in this epidemic situation: first, fast, the fastest route is because we only know the molecular sequence; second, the composition is relatively simple and relatively safe. In essence, it is to induce cells in the body to produce a protein similar to that found in viruses and trigger the immune response of the human body. Third, the production process is relatively simple, easy to mass production.

How to break through the limitation of cold storage and storage of these two vaccines? For example, Pfizer vaccines need to be stored at - 80 ℃. Modena's candidate vaccine can be stable for six months at normal refrigerator temperature (- 20 ℃), and can be stored in refrigerator for 30 days or at room temperature for 12 hours after thawing.

Huang Huang said that such extremely low temperature storage is common in research laboratories, but dry ice can be used for transportation. "Theoretically, it is a problem that can be solved. It just depends on how large-scale the government mobilizes resources to implement it."

Pfizer said in its statement on the 18th that Pfizer has rich experience in global distribution of vaccines and is confident in its expertise and existing cold chain infrastructure.

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