Not All Vaccines Are Alike
Even for those first in line for a shot, protection from the virus won’t be immediate — it takes weeks for the immune system to marshal its biological forces in the form of disease-fighting antibodies. And a vaccine that creates immunity for some people may not protect others. When a vaccine is approved for the general public, it will be the first time it's administered on higher-risk groups, which are not typically enrolled in safety trials due to the difficulty of determining the cause of adverse reactions in those populations.
"People tend to look for what's called a clean baseline in a study sample," Caplan said.
(After a vaccine is released, the Food and Drug Administration closely monitors any negative effects to determine if higher-risk groups are responding poorly.)
In addition, evidence exists that vaccines do not work in some sub-populations. For example, people over 60 do not build much of an immune response to the flu shot. The immune system of people with cancer often prevents a vaccine from working, and limited data suggests obesity reduces the effectiveness of immunizations. These groups are also the most susceptible to the worst consequences of contracting the coronavirus.
The efficacy of vaccines has a wide range. The annual flu shot is at one end of the spectrum, working 40% to 60% of the time. At the other end, the measles vaccine is about 93% effective with a single shot and 97% with two doses. The National Institutes of Health is aiming for 50% effectiveness for a COVID-19 immunization, though scientists do not know how long that immunity will last.
Vaccinologists say there's a good chance a coronavirus shot will not give you lifetime immunity.
Even once a vaccine exists, a drug company will need to manufacture billions of doses to treat populations around the world. That’s if it's just one shot. Many vaccines require more than one, spaced at least a month apart to be effective.
“In the history of vaccines, anything like cholera, cervical cancer, anything that's been a two‐shot vaccine has turned out to be a pain in the neck,” said Caplan. “People don't comply.”
It’s difficult to make billions of anything safe and reliable. Plants go offline. Parts malfunction. Shortages will likely crop up.
Making sure there is adequate access to syringes, vials, stoppers, gloves and even alcohol swabs is “going to be a challenge,” said Dr. Georges C. Benjamin, executive director of the American Public Health Association.
More bottlenecks can unfold in distribution. Shipping, trucking or flying vaccines around the globe often requires deep refrigeration, at temperatures 112 degrees below zero. Successful transport will require technical expertise and thorough planning, both of which will be a challenge in poorer nations.
The troubled rollout of coronavirus tests at the beginning of the pandemic shows just how difficult carrying out a mass vaccination program could be.
“Remember that we are going to be vaccinating everyone in the world, so that means, just like testing, there's going to be supply chain issues that we've got to work through early in the process,” Benjamin said.
Once a truck delivers the vaccine to doctors’ offices, there’s still no guarantee people will get it. A recent NBC News poll found less than half of people in the U.S. would get a government-approved vaccine, with 22% saying they wouldn't and 32% unsure. In 2019, the World Health Organization called vaccine hesitancy a threat to global health, and the antivaccine movement has been spreading disinformation since the beginning of the outbreak.
Some people believe doctors push immunizations because they receive extra government subsidies.
“Most [people] do not seem to understand that vaccines in most practices is at best a break-even proposition,” said Dr. Margot Savoy, professor of family and community medicine at Temple University. “For some practices it is actually a money-losing proposition. People are doing it because of the health of the public, not because they're making a lot of money on it.”
Savoy says many of her low-income patients worry the vaccine will be pushed on poor people to test it out.
“Your ongoing experiences with systemic racism that continues to exist in the medical system means that you're not necessarily going to trust the new vaccine that just came out,” Savoy said.
If some communities are hesitant or if supplies run short, then case counts will rise even after scientists and officials celebrate success — which could give the false impression it doesn’t work.
Early branding of the federal vaccine initiative may not have helped matters. The government called the effort Operation Warp Speed.
“I think it has given people an impression that corners will be cut,” said Dr. Walter A. Orenstein, professor of medicine at Emory University. “It has raised concerns that these vaccines are going to get by with a far lower standard than other vaccines.”
The problem is the terminology, he says, not fewer formal safety protocols.
In It Together
Even a slight reduction in vaccination rates can impede a successful immunization program. Vaccines only work if nearly everyone is on board. A measles outbreak in northeastern New York last year is a case in point: The virus took hold in a highly unvaccinated community of Orthodox Jews, leading to the longest documented outbreak in the U.S. since 2000.
Doctors estimate about 60% to 70% of the human population will have to become inoculated to stop the coronavirus, which will require sophisticated planning, governmental cohesion, and extensive public health education. When exactly all that will come together is unclear.
“I’d like to firmly come down on, ‘Beats me,’” said Dr. Paul Offit, the director of the Vaccine Education Center at Children’s Hospital of Philadelphia. “I am no longer making guesses about this virus.”
While a lot can go wrong, he hopes a lot will go right, because a vaccine is our best option to develop community immunity.
“If you look at smallpox, polio, measles, you can see the dramatic impact we've had in terms of reduction of disease,” said Dr. Julie Morita, executive vice president at the Robert Wood Johnson Foundation. “We have had major successes with vaccines, and that's why there is so much great hope for this COVID vaccine.”
In the meantime, the pandemic drudgery of masking up, social distancing and quarantining will have to continue if we are to prevent the deadly coronavirus from spiraling out of control … again.