Last month Pfizer’s and Moderna’s Covid-19 vaccines came out with promising results. The experimental vaccines were shown to be 90 percent and 94.5 percent effective at protecting people from infection. Following these results, Senator Rand Paul made a controversial tweet. According to him, “naturally acquired” immunity from Covid-19 offered better protection with a 99.9982 percent rate of effectiveness.
The senator who was diagnosed with Covid-19 this year argues that surviving the disease after contracting it gives greater protection, and has lower downsides, than getting vaccinated.
The problem with this train of thoughts is that there’s no way to predict who will survive an infection unscathed, said Jennifer Gommerman, an immunologist at the University of Toronto. There are too many external factors that could affect a person’s survival rate such as local hospital capacity, or the strength of the infectee’s immune system. That’s why choosing to purposely catch the disease over the vaccine is “a very bad decision,” she said. She explains the main benefit of a vaccine is that it’s predictable and safe. “It’s been optimally tailored to generate an effective immune response.”
Is a vaccine or natural infection better?
The short answer is that nobody knows, not even experts in the medical field. The reason for the ambiguity is because there have been cases of vaccines outperforming natural infection and vice versa.
One example of a natural infection being better than a vaccine is having humps. Contracting the illness naturally generates lifelong immunity, but some people who have received one or two doses of the vaccine still get the disease.
On the other hand, volunteers who participated in the Moderna shot trial ended up having more antibodies in their blood than people who had been sick with Covid-19. This study is by no means conclusive as the sample size was limited to only 34 healthy adults.
Natural immunity = High risk
The majority of people who’ve survived a bout with the coronavirus produce some antibodies and immune cells in order to fight off the infection. And the evidence so far suggests that this protection will persist for years, preventing serious illness, if not reinfection.
But the immune response can vary dramatically from one individual to another, with a 200-fold difference in antibody levels.
In people who were only mildly sick before recovering, the immune protection that can prevent a second infection may decrease within a few months. “Those people might benefit more from the vaccine than others would,” said Bill Hanage, an epidemiologist at the Harvard T.H. Chan School of Public Health.
One possible cause for the differences in immune response from a natural infection might be due to the amount of virus to which a person is exposed to.
Vaccines are predictable
With a vaccine, everyone gets the same dose. “We know the dose that is being administered, and we know that that dose is effective at eliciting an immune response,” Dr. Gommerman said. “So that becomes a variable that’s taken off the table when you get the vaccine.”
People who are obese, or have diabetes are particularly susceptible to severe cases of Covid-19, where they may end up on ventilators. But even to this day, doctors have no idea why some people get very sick and die while others remain asymptomatic.
In a study of more than 3,000 people, ages 18 to 34, who were hospitalized for Covid, 20 percent required intensive care and 3 percent died.
“It’s true that most people aren’t going to be hospitalized, most people aren’t going to get in the intensive care unit or die,” said Dr. Yvonne Maldonado, who represents the American Academy of Pediatrics at the meetings of the federal Advisory Committee on Immunization Practices.
But “nobody is immune to severe disease,” she said. And even if healthy people are not at high risk of Covid themselves, others could be. That’s why we wear masks and practice social distancing.
At the end of the day, doctors and researchers alike all seem to agree that covid-19 vaccines are the safer option regardless if you’ve already been infected or not.