On Monday November 9, the pharmaceutical companies Pfizer and BioNTech announced positive Phase 3 results for their coronavirus vaccine candidate. Data suggests their vaccine is over 90% effective in preventing the transmission of COVID-19. This was better news than most experts had anticipated; virologists were hopeful for 70% efficacy and a growing consensus was that a 50% success rate would have cleared the bar for approval.
Additional safety data should be ready within two weeks. Assuming the vaccine is officially deemed safe – there have not been any major problems in trials involving tens of thousands of volunteers - Pfizer and BioNTech will apply for emergency use authorization from the Food & Drug Administration (FDA) by month-end. Immunizations could begin in December; there are 50 million doses (25 million vaccines) ready to be deployed. A vaccine requires two jabs. The firms aim to produce 1.3 billion doses in 2021.
Results from another biotechnology company called Moderna are expected imminently. Hopes are elevated for another dose of positive news; the properties of Moderna’s vaccine are similar to that of Pfizer and BioNTech’s.
A Dose Of History
Throughout history, some of the most important medical breakthroughs involved the successful development of vaccines that neutered an array of highly infectious diseases. Despite some misinformation or shall we say, “fake news,” spread by anti-vaxxers, approved vaccines are very safe and extremely effective.
Below is an abbreviated history coupled with interesting supplemental information on some of the most important vaccines ever developed.
1796: Smallpox. The smallpox virus was caused by two related pathogens, Variola major and Variola minor. Smallpox was one of the most infectious, debilitating, and deadly diseases known to mankind. ~30% of patients who became infected, died. Many of those who survived were left permanently disabled and or disfigured.
Although attempts at inoculation date back to the 1500s, the British physician Edward Jenner is credited with developing the first (albeit rudimentary) smallpox vaccine. Doctor Jenner observed that milkmaids infected with a mild virus called cowpox seemed to be immune from acquiring smallpox. To test his hypothesis, Jenner deliberately infected a small child with cowpox. He accomplished this feat by scratching the boy’s arm and introducing the open wound to the cowpox virus taken from the pustules of an infected milkmaid. A few months later, Doctor Jenner attempted to infect the boy with the deadly smallpox virus via pus taken from an existing smallpox victim. He was not successful. Jenner’s initial suspicion was correct; the cowpox virus had indeed conferred immunity to the deadly smallpox virus. Until a more efficient smallpox vaccine was developed in the mid 1850s, antibodies from the cowpox virus helped protect people against smallpox.
Unfortunately, mankind did not gain an upper hand on the smallpox virus until the back half of the 20th century, when a massive coordinated global inoculation effort resulted in the disease officially being declared eradicated in 1980 (the last naturally occurring case was documented in 1977; the last outbreak in the United States occurred in 1949). To this day, smallpox is the only disease that has officially been 100% eradicated; thank goodness. To put in perspective how deadly smallpox was, consider the following data: In the last 100 years of its existence – 1880 to 1980 - smallpox is thought to have killed ~500 million people. We had to triple check this estimate to ensure it was accurate.
1885: Rabies. Rabies is a virus mainly found in animals including bats, raccoons, dogs and cats. Humans can become infected via a bite of a sick (rabid) animal. Most untreated rabies victims die. In 1885, Louis Pasteur and Émile Roux developed the first successful vaccine against rabies using infected tissue from a deceased rabbit’s spinal cord. Today, rabies is very rare in the United States. Less than 100 cases have been officially documented since 1990 (thousands have been treated for possible exposure). Rabies inoculation is not recommended unless a person is potentially exposed (the rabies vaccine is effective post-exposure) or is planning to travel to a country where the disease is still prevalent.
1897: Bubonic plague. The bubonic plague or “black death” is caused by the Yersinia pestis bacteria. In the pre-antibiotic era, 60% of people who became infected with the plague perished. The black death killed tens of millions of people. In one particularly acute outbreak in the medieval era, the plague wiped out one third of Europe’s population. In 1897, a man named Waldemar Haffkine developed a vaccine using minute amounts of Yersinia pestis to induce partial immunity. He tested the vaccine on prisoners, and himself. Though Haffkine’s vaccine was only partially efficacious and had unwelcome side effects, it did reduce the risk of catching the plague by ~50%.
1926: Pertussis (whooping cough). Pertussis, more commonly referred to as whooping cough, is caused by the bacteria Bordetella pertussis. Doctor Leila Denmark was credited with developing the first vaccine to combat Pertussis, in 1926. This impressive feat was but one of her many achievements in (and out) of the medical field. Leila Denmark was born on February 1st, 1898 in Portal, GA. She was the only woman in the 1928 graduating class of the Medical College of Georgia. This trailblazer practiced medicine until she was 103 years old. Throughout her illustrious career she won numerous awards, penned two books, and was among the first doctors who advocated avoiding smoking around children. She lived independently until she was 106 years old. She died on April 1st, 2012 at the age of 114.
1952: Polio. Polio is a highly infectious disease caused by the poliovirus. It is communicated via oral to fecal contact. Asymptomatic transmission is common; ~70% of polio victims never exhibit symptoms. Approximately 25% of polio victims experience flu-like symptoms (sore throat, fever, tiredness, etc) and a smaller subset become afflicted with paresthesia (pins and needles) and meningitis. Approximately 1 of every 200 polio victims become paralyzed. Of those, ~5% will perish because the virus paralyzes the muscles in the diaphragm needed to breathe. In something called post-polio syndrome, children who become infected become symptomatic decades later, in adulthood.
A virologist named Hilary Koprowski developed a prototype polio vaccine in 1950. In 1952, Jonas Salk developed an effective polio vaccine. In the mid 1950s, a global inoculation effort commenced. The last documented transmission in the United States occurred in 1979. Today, polio has been eradicated in every country except Pakistan and Afghanistan.
Perhaps the most prominent association with polio is the Iron Lung, a mechanical breathing device that helped polio victims with paralyzed diaphragms. In the 1940s and 50s, these machines were utilized in hospitals across America. As of 2014, there were only 10 American’s still using an Iron Lung.
1963: Measles, (1967) Mumps, (1970) Rubella. Administered together, the Measles, Mumps & Rubella vaccine (MMR) was combined in 1971. MMR is one of the most widely dispensed vaccines in the world. In the United States, since immunizations began, cases of measles dropped from hundreds of thousands per year to hundreds per year. The mumps have been reduced from ~200,000 cases per annum to ~2,000. Instances of rubella have been slashed from ~50 thousand per year to almost nil.
1981: Hepatitis B (HBV). Hepatitis B and HIV are communicated in many of the same ways, but Hep B is over 50x more infectious than HIV. According to the Centers for Disease Control, 1.2 million people in the United States and ~350 million people worldwide are infected with hepatitis B. Most are unaware of their condition. Typically, Hep B “clears” on its own and the majority of those affected make a full recovery. However, in a few percentages of cases, the disease becomes chronic and can progress to cirrhosis. The HBV vaccine marked a medical milestone in being the first vaccine that prevented a type of cancer.
1995: Chickenpox. Dr. Michiaki Takahashi developed an early version of a chickenpox vaccine in the mid 1960s; however, a vaccine was not licensed for use in the United States until 1995. The reason: there was a considerable amount of debate among medical experts about the costs and benefits of inoculating children against the chickenpox, caused by the varicella-zoster virus (VZV). Virologists not in favor argued that chickenpox, though highly infectious, was not serious enough to warrant a national inoculation program. Indeed, most cases of VZV are self-limiting and resolve without medical intervention. In fact, before the vaccine, some parents purposefully exposed their young children to chickenpox because > 99% of cases (in children) resolve without major complications but VZV can be very serious in adulthood.
Before its introduction in the mid 1990s, ~4 million people – usually children – became infected with chickenpox each year, ~10,000 were hospitalized, and ~100 died. Ultimately, a decision was made in favor of national vaccination.
1998: Lyme Disease. A vaccine to prevent lyme disease, a bacterial infection transmitted by ticks, was developed in 1998 and shown to be ~80% effective in blocking the transmission of the disease. However, it was discontinued after only four years because of tepid demand. A commercially manufactured vaccine against lyme disease is not currently available in the United States.
2006: HPV (human papillomavirus). There are over 100 variants of human papillomavirus or HPV. Almost all sexually active adults acquire one or more types of HPV at some point during their lifetimes. Fourteen strains of HPV are known to cause primarily cervical cancer, but also throat, penile, tongue, and anal cancers (almost all cervical cancers are caused by HPV). Fortunately, most people eliminate or “clear” HPV on their own. However, if HPV lingers and is not treated, it can be deadly. An HPV vaccine developed in 2006 blocks four of the most common (6, 11, 16, and 18) cancerous HPV strains. The HPV vaccine was the second vaccine (HEP B) developed that prevented the transmission of a cancer-causing agent.
2019: Ebola. On December 12th, 2019, the FDA approved Ervebo, a vaccine to prevent the ebola virus disease (EVD).
2020: COVID-19? The sheer speed - less than one year from the time the genetic markers of the disease were isolated - at which a successful coronavirus vaccine appears to have been developed, is stunning. Indeed, it is a testament to the human ingenuity, cooperation, and coordination of determined researchers around the world coupled with an unprecedented amount of private and public capital stumped up to fight COVID-19.
At TQC, we applaud everybody involved in developing a safe and effective vaccine to defeat the coronavirus, another scientific breakthrough for the betterment of humanity.