Are Covid-19 vaccines the keys to freedom? Would you take it if it was offered to you today?

Published December 16, 2020, 2:31 PM

by Dr. Edsel Salvana

CLINICAL MATTERS

Dr. Edsel Maurice T. Salvana

It was the “shot” that was seen and heard around the world. On Dec. 8, the first-ever approved Covid-19 vaccine was given to a 90-year-old woman in the UK named Maggie. This became the first of many more vaccinations, marking a momentous shift in the battle against Covid-19.

The road to the Covid-19 vaccine was far from certain. Many doubted that a safe and effective vaccine could be produced in less than a year. The fastest time to develop a vaccine was four years. That was for the mumps vaccine. The preclinical and clinical studies encompassing phase 1 to phase 3 clinical trials of vaccine development are daunting. As pointed out by many scientists, though, the SARS-CoV-2 vaccine did not start from scratch. This was not a rushed process. This vaccine has been in development for the past 17 years.

When the original SARS coronavirus epidemic occurred in 2002, there was a rush to identify its weak spots. One of its vulnerabilities is its spike protein, the little knobs that give the coronavirus its distinctive appearance. Spike protein enables the virus to attack and enter human cells. The 2002 SARS outbreak fortunately fizzled out, but this meant that no vaccines could be clinically evaluated. With no more active infections, vaccines could no longer be tested.

A Covid 19 vaccine candidate at the Sinovac Biotech facilities in Beijing (Nicolas Asfouri)

When MERS emerged in 2012, there was renewed interest in developing a coronavirus vaccine. A lot of the vaccine knowledge developed for SARS was utilized to develop a vaccine for MERS. Again, the outbreak ended before clinical trials could begin. There is still some low-level transmission occurring sporadically among camel handlers in Saudi Arabia, but these are not enough to properly evaluate a vaccine. The effort to prove efficacy in humans was shelved. The SARS outbreak followed by the MERS outbreak a decade later led scientists to correctly deduce the arrival of yet another coronavirus. Scientists continued the laboratory work in hopes of being ready when the next outbreak occurred.

This foresight proved serendipitous. When Chinese scientists published the full genome of the novel coronavirus in January 2020, vaccine researchers from all over the world were ready. What followed was one of the most remarkable feats in the history of science and medicine. With international cooperation, several vaccines progressed from early phase I and II clinical trials to phase III clinical trials in just a few months. Vaccine after vaccine seemed promising as they hurdled the early phases, and doctors and scientists held their collective breaths as the progress seemed too good to be true. The US FDA set its target for approving a vaccine at 50 percent efficacy, which is a very low target. Setting the bar this low was a nod to the uncertainty surrounding this endeavor. When the data from the first phase 3 trial was reported by Pfizer, the results were stunning.

The Pfizer/BioNTechtwo-dose vaccine showed a 95 percent efficacy for prevention of Covid-19 infection among patients who had never been infected with SARS-CoV-2. Efficacy after only one dose was more than 52 percent. Just as encouraging, it showed an 89 percent efficacy for prevention of severe infection. Overall, the results from this first-ever Covid-19 vaccine exceeded the most optimistic expectations. This vaccine and the others that follow is the beginning of the end for the pandemic.

Shortly after the Pfizer announcement, other pharmaceutical companies announced their interim phase 3 trial results. Moderna, Astra/Zeneca, and Sinopharm released vaccine efficacy figures ranging from 70 percent to 95 percent.

These phase 3 trials need to be completed with at least two months of safety data, but there is every reason to be optimistic that the data will be similar to the Pfizer/BioNTechexperience. The Moderna vaccine, which is also an RNA vaccine like that of Pfizer/BioNTech, has so far shown a 95 percent efficacy for preventing symptomatic Covid-19, and 100 percent efficacy for prevention of severe Covid-19. More interim results from other vaccine studies will soon be released, and there is good reason to hope that many more effective vaccines will be available by the first quarter of 2021.

The Pfizer FDA application states that there are adverse events from the vaccine, but most of these are mild and tolerable. Some clinical trial participants reported injection-site discomfort and flu-like symptoms, but the overall safety data between the vaccine recipients and the placebo control were similar. Recent reports of severe allergic reactions in two healthcare workers who had a history of severe allergies prompted the UK health authorities to caution people with a history of severe allergies against receiving the vaccine.

Since people who had a history of severe allergies were excluded from the clinical trials, this precaution is prudent while the manufacturer and health authorities investigate the circumstances surrounding the events. They did not suspend administration of the vaccine in otherwise healthy people.

As more vaccines are released for use, more of these reactions or adverse events are expected, as is usual with new drugs. Safety data are continuously collected among those who were enrolled in the original clinical trials. The large number of subjects enrolled in these clinical trials means that any severe reaction that was missed would be very rare, with a less than one in 10,000 probability of occurrence. These rarer adverse events, if any, can be captured with good phase 4 post-marketing surveillance by manufacturers and health authorities.

I get repeatedly asked whether I would take the vaccine if it were offered to me today. As long as it is a properly approved vaccine proven to be safe and efficacious, I would not hesitate to take it. As a healthcare worker and frontliner, I am much more concerned about contracting Covid-19 that can kill me or my loved ones than the possibility of rare side effects. Covid-19 is a clear and present danger to us all, and vaccines are a way out of the constant fear of infection. I would recommend it to my parents and my in-laws who are in their 70s and their 80s respectively. I would give it to my kids once clinical data for children are available. I can’t wait for my kids to go back to physical school again. I want to be free of the constant fear that I may bring home something deadly from work. Vaccination will allow us to be with friends and family again. Vaccination will restore that most important of human experiences, the ability to touch each other and hold those closest to us.

 
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