While the most prominent COVID-19 vaccines ie. Pfizer/BioNtech, Astra Zeneca, and Johnson and Johnson are crucial in preventing hospitalizations and deaths from Covid-19. However, with efficacy rates varying for each vaccine, especially with Johnson and Johnson being of a lesser percentage than the other vaccines, consumers have started to assume the fact that vaccines with lesser efficacy cannot tackle the virus.
Thus, scientists are concerned about people developing certain negative perceptions and spreading misleading information about any kind of vaccine. This is because, at the time when the pandemic is peaking, any kind of effective vaccines become the need of the hour.
How do these vaccinations work?
The vaccines produced by Pfizer/BioNTech, Moderna, and by Johnson & Johnson reduced the fatality rate of Covid-19 by 100 per cent in comparison to their placebo group in clinical trials. All the trial recipients were placed out of the hospital to check the abilities to potentially downgrade Covid-19 from a public health crisis to a manageable problem.
“The goal of a vaccine was really to defang or tame this virus, to make it more like other respiratory viruses that we deal with, so when you look at the three approved vaccines in the US, all of them are extremely good at that metric,” said Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security.
However, the vaccines have some significant differences in respect to dosage and storage. The Johnson & Johnson vaccine involves one dose and can be stored at refrigerator temperatures, while the others require two doses and need to be kept in freezer temperatures. Further, Johnson and Johnson is also more economical in the USA market. Saad Omer, the director of the Yale Institute for Global Health, told Vox that Johnson and Johnson is a vaccine that “can increase equity.”
In early February it reported that Johnson and Johnson’s total efficacy in preventing Covid-19 cases that produced symptoms was 66.1 percent. The Moderna vaccine and the Pfizer/BioNTech vaccines reported efficacy levels of around 95 percent. Thus this gap in efficacy rates made people presume that the Johnson & Johnson Covid-19 vaccine lacks effectiveness. However, scientists believe that the efficacy levels of the Covid-19 vaccines are relative to the clinical trials that produced them, and these trials did not follow the same procedures and conditions.
Although these vaccines have varying efficacy rates, researchers are discovering that the Covid-19 vaccines as a whole are contributing to keeping people safe and alive from the virus. Hence, experts suggest getting vaccinated the earliest with any of the brands available, i.e. the first vaccine you get your hands on. “That’s how I think of these vaccines, as basically interchangeable,” said Adalja.
Why cant these vaccines be directly compared?
Every COVID-19 vaccine undergoes individuals tests of its own in several stages to gauge the safety, dosage amounts, and efficacy. Thus, they ideally cannot be compared against each other.
However, health officials have mentioned that the earlier results of the Moderna and Pfizer/BioNTech vaccines shifted expectations of the Johnson & Johnson vaccine.
“If this had occurred in the absence of a prior announcement and implementation of a 94, 95 percent efficacy [vaccine], one would have said this is an absolutely spectacular result,” said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, about the Johnson & Johnson vaccine during the press conference in January.
Covid-19 vaccines were tested in actual people against the actual virus in stage three of clinical testing. This involves testing tens of thousands of participants randomly divided into two groups where one group receives the ACTUAL vaccine and one receives the placebo. This is done to study how the vaccines react to possible threats of catching the virus. Thus, real-world testing involves factors of volunteers being exposed to different geographical conditions where the number of cases varies. There are also differences in the restrictions to tackle the virus and further the varying access to health care.
The time when the vaccines were enrolled to the participants also plays an important role. The Moderna and Pfizer/BioNTech finished enrolling participants in their phase 3 trials in October and reported their results in late November. The Johnson & Johnson phase 3 trial only finished enrolling participants in December 2020 and reported their results in January.
This implies that the Johnson & Johnson vaccine was tested during one of the most severe stages of the pandemic, where the situations were much intense across the world. It not only battled high transmissions and hospitalizations in the second wave in many places but also was exposed to the new variants of the coronavirus that had emerged during this time.
Thus the fact that these vaccines were tested in different ways at different times is the reason why one cannot make direct comparisons. “I don’t even look at those efficacy numbers and compare them head-to-head like that,” Adalja said. “Biostats 101: You cannot compare trial results like that unless they were done in a head-to-head fashion.”
Hence, vaccines are also judged based on their supplies, costs, the logistics of deploying them, the durability of the protection they offer, and their ability to fend off emerging viral variants. Thus, although people find it tempting to look only at the efficacy rates and determine the effectiveness, each measure of efficacy comes with a degree of uncertainty, and trials might have faced different criteria depending on severe situations of COVID-19, or comparatively moderate conditions.
David Kennedy, who studies the ecology and evolution of infectious diseases at Pennsylvania State University in University Park says that the vaccines were studied at different times in various countries. Each trial can only offer a snapshot of protection against the viral variants that were dominant in that time or place.
“That number relates to a particular point in time,” he says. “How that translates into protection over one to two years is not the same,” says Kennedy.
The Way Forward
Vaccines are effective to prevent catching the virus, and not completely eradicating it. Thus, although these jabs prevent hospitalizations and death, it doesn’t mean that they completely prevent the symptoms of Covid-19. Thus, vaccinated people still require to follow the norms and require to wear masks till the vaccinations drive are widespread.
All of the currently available COVID-19 vaccines work towards reducing deaths, hospitalizations, symptoms, and transmission in different volumes, and thus there is not any particular ‘ideal’ vaccine.
“I wouldn’t be picky if I’m a high-risk person, because being picky may leave you out in the cold of not being vaccinated,” said Lawrence Corey, a professor studying virology at the Fred Hutchinson Cancer Research Center. “We have still an incredible epidemic going on here.”
The vaccine may amount to some side effects, and thus the people suffering from severe allergic reactions or certain immunological conditions have to be extra precautious while selecting a vaccine and it might happen that some may be unable to be inoculated with one. This makes it further crucial to vaccinate everyone around a vulnerable person, to build herd immunity.
There is rising concern and apprehensions about how these vaccines will be efficient enough against the new emerging variants as the SARS-CoV-2 virus continues to mutate. Hence, vaccine manufacturers are looking at booster doses and modifications in vaccine shots as a way to tackle the virus in a better way.
Researchers too are evaluating how well the existing vaccines are holding up against the variants in the real world. As a way to gauge better conclusions, scientists should ideally coordinate, share protocols, and pool data about the various clinical trials that were independently conducted for each vaccine.
“Imagine what will happen when these studies generate results, each with their own populations, eligibility criteria, validation procedures, and clinical endpoints,” wrote Natalie Dean, an assistant professor of biostatistics at the University of Florida, in Nature. “If we don’t want our final answers to be a jumble, we must act now to consider how data can be compared and combined.”
Meanwhile, it is also indispensable to realize the fact that getting vaccinated does not mark the end of the virus, and these are one part of the ways to tackle COVID-19. Social distancing, hand-washing, mask-wearing, testing, tracing, and isolation remain extremely important as a tool to fight and eradicate the virus.