More than any other recent event, COVID-19’s rapid global spread reminds us of the promise of vaccines and the peril of life without them.
Efforts to combat the virus without the help of a vaccine recall the tragic history of pandemics hundreds of years ago, before the arrival of vaccines, when diseases struck communities with devastating results.
In the worst cases, influenza, smallpox, and other diseases moved so rapidly they wiped out entire populations that had no protective immunity to the disease.
Smallpox, an infectious disease that causes fever and rash, killed about 3 out of ten people, resulting in hundreds of millions of people dying before vaccines were administered.
Signs of smallpox can be seen in Egyptian mummies from three thousand years ago. By the early 1500s, Spanish and other travelers brought the disease to the Americas, causing the deaths of millions of indigenous peoples over the next centuries, and weakening the Incan and Aztec empires.
After vaccination programs began, the disease was gradually eradicated throughout the world, with the last known cases occurring in the 1970’s, according to the Centers for Disease Control.
Influenza has not been eradicated, but its severity and lethality have been greatly reduced because of annual vaccination programs.
The vaccine helps keep you from getting ill, or it can make you less sick if you do become infected, says Dr. Keith Lamy, at Austin family practice medicine clinic.
It also helps achieve herd immunity, reducing the risk to those who are not vaccinated and preventing the disease from spreading rapidly.
Usually, those who get influenza have fever, fatigue, and aches for several days and then feel better. But some develop pneumonia or other serious problems, and in severe cases they may die.
If you are exposed to the virus through a vaccine or infection your body’s immune system creates antibodies to combat the virus if you are infected again.
But influenza viruses can mutate, creating new strains. If the change is big enough, people may have limited or no immunity, resulting in much more severe symptoms. If the strain spreads throughout the world, it results in a pandemic.
For sheer killing power, no pandemic has matched the deadly force of the Spanish Influenza from 1918 to 1919. Up to one-third of the world’s population became infected, and as many as 50 million or more people died, many under age 50 and in the prime of life. In some cases, people died just a few hours after feeling sick, with grisly symptoms that included bleeding from the eyes, ears, nose and mouth.
No vaccine existed to protect people, so communities used the only weapons they had–quarantines, good hygiene, masks, and restricting gatherings– to help control the spread.
Today, vaccines exist not only for seasonal flu, but for many other diseases that used to cause serious illness, disfigurement, and death.
Vaccines have been so successful against diphtheria, measles, pertussis, and polio that we tend to forget how much misery they caused.
Outbreaks of polio in the 1940s, for example, inspired fear in US parents over concern their children would be infected and develop meningitis and paralysis, sometimes resulting in death.
The United States has been free of polio since 1979, thanks to widespread vaccination programs.
But with anti-vaccination sentiment growing in parts of the United States, some diseases are making a comeback. Highly infectious measles, which had been eliminated, had a resurgence last year, with 1,282 cases in 31 states, according to the CDC.
Some parents cite religious or philosophical reasons for not allowing children to be vaccinated. Although no link has been found between the measles vaccination and autism, some believe there is a connection, and they spread that belief through social networks.
As scientists race to develop multiple vaccines to prevent COVID-19, the promise of an effective tool is bringing hope to many Americans who have seen their lives disrupted and health threatened by the disease. A vaccine will likely be available to many Americans by the middle of next year, but some high risk individuals may get it earlier than that.
To reduce the threat to themselves and to others, many Americans are willing to receive a vaccine that may not be as effective or even as safe as other time-tested vaccines, according to polls.
Yet others do not view a vaccine as favorably and may take a more wait-and-see attitude. Polls show as many as a third or more of Americans may be reluctant to get the vaccine because of concern the speed of development may compromise safety.
Even if people do get the vaccine, it will likely have limited value. A vaccine only needs to be at least 50% effective, meaning a person would be 50% less likely to get COVID, according to FDA guidelines for vaccine makers.
While that would significantly reduce case numbers and improve the public health outlook, it may not be the “magic bullet” in protection that many people are seeking.
Although no vaccine is 100% effective, some vaccines, such as for measles, have an efficacy greater than 90%.
Potentially lower efficacy, coupled with uncertainty over how long the vaccine will protect people, means any COVID vaccine will likely be a crucial, but imperfect tool for combatting the disease.
For the near future, masks, hygiene and social distancing will likely be needed, even as vaccines are unrolled sometime next year.