As European and American countries enter the stage of substantive approval of the coronavirus vaccine and prepare to start mass vaccination from the elderly and front-line medical staff, the issue of vaccine safety has become more realistic.
On Wednesday, Canada became the second country after the United Kingdom to officially authorize the emergency use of the coronavirus vaccine. On Thursday, the FDA Advisory Committee will meet to discuss whether the efficacy and safety data of Pfizer and Baintech’s vaccines meet expectations and decide whether to grant emergency authorization authorization to them.
Death or no connection with vaccine
According to a brief released on the FDA’s official website, Pfizer and Baintech’s three-phase clinical randomized controlled trial of the BNT162b2 vaccine involved about 44,000 participants. Effectiveness data show that eight cases in the vaccine group were infected with COVID-19 and 162 in the placebo group seven days after the second dose of vaccination showed that the vaccine was effective at 95%. In addition, two months of follow-up data showed that among participants aged 16 and above, the dose of the vaccine was It shows good security at 30μg. On November 20, Pfizer and Baintech submitted an emergency authorization application for the use of vaccines to the FDA.
According to FDA documents, the emergency use authorization requires all safety data accumulated in vaccine research, including phase I and phase II clinical data focusing on serious adverse events in study participants, adverse events of special concern and severe cases of COVID-19.
Phase III safety data should include characteristics of the reactivity of a sufficient number of participants in the relevant age group (common adverse reactions and expected adverse reactions that occur soon after vaccination) and should include a high proportion of participants in the group (more than 3,000) who followed up for serious adverse events to view Check whether there are adverse events requiring special attention within at least one month after completing the complete vaccination program.
In particular, FDA emphasizes that data from the Phase III study should also include a median follow-up time of at least two months after the completion of a complete vaccination program to help provide sufficient information to assess the risk of vaccine benefits.
“It is generally believed that adverse events associated with vaccination usually begin within 6 weeks after vaccination. Therefore, a two-month follow-up period can determine potentially immunomediated adverse events that begin within six weeks of vaccination.” FDA documents say. FDA documents also show that from the perspective of vaccine efficacy, it is important to assess whether immune protection effects mediated by early response begin to weaken.
In the FDA report, the “serious adverse events” of Pfizer and Byntech vaccines were specifically mentioned. Of the 43,448 participants in vaccination, the reporting period from April 29, 2020 to November 14, 2020, the death toll was 6, 2 were in the vaccine group and four were in the placebo group. Both of the vaccinated deaths were older than 55 years old, one of whom suffered cardiac arrest 62 days after vaccination and died three days later, and the other died of arteriosclerosis three days after vaccination; three of the four deaths in the placebo group occurred in people older than 55.
For the above deaths, the FDA did not find a direct link to vaccination. A vaccine expert told First Financial Reporter: “The question now is whether it can be confirmed whether the two deaths in the vaccine group were caused by vaccination. Because in vaccine clinical trials, it is also normal for subjects to die for unrelated reasons. Judging from the reported causes of death alone, it seems that there is little to do with vaccination.”
He also stressed that the potential risk of mRNA nucleic acid vaccine lies in the lipid nanoparticles (LNPs) used to transfer and nucleic acid drugs. Although this technology is a relatively mature RNA transfer technology, since there are no cases of commercialization of this vaccine, its risk should still be monitored.
Among all 43448 subjects with nonfatal severe adverse events, the proportion of subjects in the vaccine group and placebo group that reported at least one severe adverse event was 0.6% and 0.5%, respectively. The most common value in the vaccine group was higher than that of the placebo group. The serious adverse reactions in the placebo group were tailingitis, acute myocardial infarction and cerebrovascular accidents; the placebo group was higher than that of the severe adverse reactions in the placebo group, which were pneumonia, atrial fibrillation and syncope.
Among other adverse events, four cases of Bell’s palsy were reported in the vaccine group, and no similar adverse events were reported in the placebo group. According to FDA documents, clinical Bell’s palsy is not a serious adverse event.
According to the guidance for the treatment of Bell’s paralysis published online by the American Medical Association (AAN) in the Journal of Neurology on November 7, 2012, Bell’s paralysis is common, with an annual incidence rate of 20 per 100,000 people. In these cases, 70% to 85% of patients can relieve themselves without treatment.
An expert from the Drug Alert Department of a domestic biopharmaceutical company told the First Financial Reporter: “At present, the main view of the FDA does not believe that these cases of Bell’s paralysis are vaccine-related, and the incidence rate is consistent with the basic incidence of the population. It only needs to be monitored in the long term in a large number of people.”
People with a history of allergy should not be vaccinated.
“This FDA document contains a lot of information and is very useful.” A domestic vaccine researcher told First Financial Reporter, “We are finally pleased to see a detailed data report on vaccine efficacy and safety.”
“The FDA’s approach is very transparent, and the approval process represents the highest standards in the world.” “The FDA is expected to announce the vaccine authorization decision on Friday after the advisory committee’s outside experts gave voting recommendations Thursday,” Brad Longka, founder of bioinvestment fund Loncar Investments told First Financial Reporter. He also said that this process, which usually lasts for weeks, will be greatly reduced under the coronavirus epidemic.
On Wednesday, the UK revised vaccination recommendations after the National Health Service (NHS) reported that two of the agency’s staff had allergic reactions related to vaccinations, saying that “no one who has a serious allergic reaction to vaccines, drugs or food should not be vaccinated with Pfizer and BioNtec” h) Coronavirus vaccine”.
Vaccine-related stocks fell sharply that day, with Pfizer and Byntech falling 1.67% and 4.14% respectively on the same day; Moderna’s share price plummeted 7.8% and AstraZeneca’s share price also fell 1.24%.
However, two vaccinators with allergic reactions are currently recovering, and the UK’s drug administration will conduct further investigation as a priority to collect more information. Pfizer and Byntech also said that they are fully cooperating to support the investigation.
In response, experts from the above-mentioned domestic biopharmaceutical company Medical Alert Department told the First Financial Reporter: “To report two cases of allergic reactions after the listing in the United Kingdom, further information needs to be monitored. But from current information, a history of severe allergies may be the cause of allergic reactions.”
A public health expert told First Financial Reporter: “This is the right approach. There are many reasons for allergies, and the situation of each vaccine is different. Anyone with a history of allergic diseases should not be vaccinated until the cause of allergic reactions by vaccination.
The above-mentioned experts also said that it is normal for vaccines to have side effects, especially after large-scale vaccinations are started, and the key is to weigh risks and benefits.
