Pfizer provides strong protection against Covid after the first dose of the vaccine

According to documents published 8^th December 2020, by the Food and Drug Administration before a meeting of its vaccine advisory committee, the coronavirus vaccine developed by Pfizer and BioNTech provides good protection against COVID-19 within about 10 days of the first dose.

The discovery is one of several significant new findings outlined in the briefing materials, which contain more than 100 pages of agency and Pfizer data analysis. Pfizer and BioNTech revealed last month that their two-dose vaccine had a 95 percent efficacy rate after two doses were administered three weeks apart. The new studies show that protection starts kicking much earlier.

What is more, regardless of the race, weight or age of a volunteer, the vaccine worked well. While no significant adverse reactions caused by the vaccine were discovered in the trial, several patients suffered aches, fevers and other side effects.

Akiko Iwasaki, an immunologist at Yale University, said, "This is what an A-plus report card looks like for a vaccine." On 3 December 2020, in advance of a vote on whether to approve the authorisation of Pfizer and BioNTech vaccines, the FDA Vaccine Advisory Panel will address these materials.

In July, Pfizer and BioNTech started a large-scale clinical trial, employing 44,000 individuals in the United States, Brazil and Argentina. Half of the volunteers received the vaccine, and half got the placebo. According to one graph in the briefing materials, new coronavirus cases rapidly tapered off in the vaccinated group of volunteers about 10 days after the first dose. In the placebo community, cases continued to grow gradually.

The rapid impact of the vaccine could help not just the individuals who get it but the overwhelmed hospitals of the nation, curbing the influx of new patients into intensive care units.

It is unclear, in spite of the early safety afforded by the first dose, how long that protection will last on its own, underlining the value of the second dose. Previous studies have shown that the second dose of the Pfizer-BioNTech vaccine provides a substantial long-term boost to the immune system, an effect that is seen in many other vaccines.

According to Dr. William C. Gruber, senior vice president of Pfizer Vaccine Clinical Research and Development, the vaccine's effectiveness after the first dose is about 52 percent. That rises to about 95 percent after the second dose . "Maximum protection is provided by two doses of vaccine," he said.

Many experts have expressed concern that some individuals may be better protected than others by the coronavirus vaccines. But no such concern is suggested by the findings in the briefing materials. In both men and women, the vaccine has a high efficacy rate, as well as comparable rates in white, black and Latino individuals. It has also performed well in obese individuals with a higher risk of COVID-19 illness.

In older adults, certain vaccines for other diseases cause a poor immune response. Yet Pfizer and BioNTech found that people over 65 received as much coronavirus vaccine protection as younger individuals did. "I found myself trembling reading this said Dr. Gregory Poland, a Mayo Clinic vaccine researcher, referring to the strong vaccine response in obese and older individuals. "By any measure, this is a grand slam."

The trial will proceed even if the vaccine is approved by the FDA. The companies claimed in the briefing papers that they would allow individuals to remain as long as possible in the experiment, not knowing if they received the vaccine or the placebo, so that the researchers could continue to gather information about whether the vaccine was safe and successful. The briefing materials also provide a closer look at the vaccine's efficacy. Any individuals who get vaccines encounter health problems that have little to do with the vaccine itself in any large clinical trial. It can point to symptoms that can potentially be triggered by a vaccine by contrasting their symptom rates with those of the placebo community as well as with background rates in a population.

The FDA concluded that there were no "meaningful imbalances" between the two classes involving severe health complications, known as adverse events. The agency noted that a form of facial paralysis called Bell's palsy was encountered by four people in the vaccinated community, with no cases in the placebo group. The difference was not meaningful between the two groups and the incidence was not substantially higher in the vaccinated group than in the general population.

The latest Pfizer study showed that in the hours following the second dose, many volunteers who obtained the vaccine felt sick, indicating that many individuals would have to take a day off work or be prepared to rest before the symptoms subside. More than half of those aged 16 to 55 developed fatigue, and more than half also registered headaches. Just over a third were experiencing chills, and 37 percent were feeling muscle pain. Approximately half of those older than 55 felt tired, a third developed a headache, and about a quarter felt chills, while muscle pain was experienced by 29 percent.“It is a wise decision to anticipate taking a day off after the second dose,' Iwasaki said.

A first-person account of the symptoms she encountered as a participant in the Pfizer-BioNTech study, which included chills, nausea, headache and fever, was reported on 7 December 2020 by Kristen Choi, a psychiatric nurse and health services researcher at the University of California, Los Angeles.

Choi wrote in the journal JAMA Internal Medicine, "Clinicians would need to be prepared to discuss with patients why they should trust the vaccine and that its adverse effects might look a lot like COVID-19. She told physicians to tell patients that these unpleasant symptoms were a sign that, despite the unfortunate similarities with the symptoms of the disease, the vaccine is working."