[ad_1]
In just one week, efficacy results of between 90% and 95% were announced for three experimental vaccines for covid-19, two North American and one Russian, based on preliminary data from clinical trials in the last phase.
In this “cold war” for a vaccine against a respiratory disease that is afflicting the world, caused by a new virus, a third element appears, China, which promises to release, in November, the first efficacy results for a vaccine in test in Brazil, Indonesia and Turkey.
Despite the “encouraging news” about possible vaccines for covid-19, the World Health Organization calls for caution, as more data needs to be analyzed to accurately measure its efficacy and safety profile, without which it cannot be administered.
Here are some essential points on the subject:
+++ WHAT ARE THE EFFECTIVENESS RESULTS OF EXPERIMENTAL VACCINES ALREADY REPORTED? +++
On November 9, American pharmaceutical multinational Pfizer and German biotech partner BioNTech announced that their experimental vaccine for covid-19 was 90% effective, based on analysis of 94 cases of covid-19.
Two days later, the manufacturer of Russian competitor Sputnik V announced a 92% effectiveness, based on data from 20 cases.
Most recently, on Monday, November 16, the American biotech company Moderna indicated that its candidate vaccine is 94.5% effective in preventing covid-19, taking into account the analysis of 95 cases.
+++ WHAT TECHNOLOGIES ARE USED IN THE MANUFACTURE OF THESE CANDIDATE VACCINES? +++
Both Pfizer and Moderna’s experimental vaccines are based on genetic messenger RNA technology, which uses the person’s body to make a key protein from the coronavirus covid-19, in this case the spike protein, “the gateway to entry” of the virus. in the cells and stimulates the immune system to create antibodies against the virus.
Once injected, this type of vaccine instructs healthy cells to make copies of the SARS-CoV-2 coronavirus spike protein, stimulating the production of neutralizing antibodies.
After being infected with the virus, the body is able to recognize it and fight it.
The Russian experimental vaccine is different, it induces the creation of antibodies to the coronavirus covid-19 through two distinct adenoviruses that have been genetically engineered to produce the SARS-CoV-2 spike protein.
+++ HOW MANY DOSES ARE NEEDED? +++
Pfizer’s and Moderna’s candidate vaccines are given in two doses. Pfizer is over three weeks, Moderna four weeks away.
The two modified adenoviruses that make up the composition of Sputnik V, authorized in Russia before the start of the final tests of efficacy and safety, are injected three weeks apart.
+++ WHAT ARE THE CONDITIONS OF STORAGE AND CONSERVATION? +++
In this regard, Moderna’s experimental vaccine seems to score points compared to Pfizer’s. The modern biotech firm claims that its candidate can be kept for six months at a temperature of -20ºC, equivalent to the temperature of most home or medical freezers.
In places where the vaccine is administered, the storage temperature can rise between 2ºC and 8ºC, and the vaccine can be stored in the refrigerator and, under these refrigerated conditions, Moderna expects it to remain stable for 30 days.
The Pfizer candidate must be stored at much lower temperatures, below minus 70ºC, days before use, which can be a logistical obstacle to its administration.
+++ IF APPROVED, HOW MANY VACCINES MAY BE AVAILABLE? +++
Pfizer and Moderna intend to ask the North American regulator for the emergency use of their experimental vaccine against covid-19, again in November, as soon as additional data certify its efficacy and safety.
Pfizer aims to have up to 50 million doses available by the end of 2020, enough for 25 million people, and to produce up to 1.3 billion doses in 2021.
The European Union has signed an agreement with Pfizer-BioNTech for the purchase of 200 million doses, with the possibility of purchasing 100 million additional doses.
Moderna plans to produce 20 million doses by the end of 2020 – the equivalent of vaccinating 10 million people. The initial batch will be destined for the United States.
+++ WHAT ARE THE DOUBTS? +++
The efficacy results, although initial, were announced by the manufacturers of the experimental vaccines, but have not been scientifically examined.
On the other hand, more confirmed cases of covid-19 are needed among the thousands of study participants to consolidate the efficacy and safety profile of the vaccines under consideration. Pfizer sets the bar at 164 cases and Moderna at 151 before proceeding with the request for emergency use.
It is not known how long the protection afforded by these experimental vaccines lasts, if they can prevent people (including those without symptoms) from transmitting the virus, if they only reduce the most severe forms of the disease, or if they work well in groups more vulnerable to infections, such as the elderly and / or with chronic diseases.
Moderna’s candidate vaccine appears, according to the biotech company, to be effective in preventing the most serious infections, as there were no serious cases of covid-19 among the volunteers who received the vaccine, compared to 11 people who were injected with a placebo. .
According to preliminary data from Moderna, only five participants who received two doses of their experimental vaccine fell ill, compared with 90 who received a placebo. The efficacy of the potential vaccine was measured two weeks after the administration of the second dose.
In the case of the Pfizer vaccine candidate, the pharmacist did not indicate how many volunteers were infected after receiving the vaccine or placebo. The efficacy of the indicated experimental vaccine, 90%, in a total of 94 cases identified with covid-19, was measured one week after the volunteers received the second dose.
Not enough time has passed since inoculation to see if there are any significant long-term side effects.
Some participants in the Moderna study showed severe fatigue, muscle, joint, and head pain after vaccination, effects that the company says are short-lived.
.
[ad_2]
Source link
