As the Covid-19 coronavirus ravages the world it’s common to hear government and public health officials say that life can’t return to normal until we get a vaccine. Will most people feel relieved once they have the option to be vaccinated? Will enough people get vaccinated to reduce the spread of Covid-19?
First it’s important to understand how vaccines in general have improved our lives and address the concerns of people who might have a skeptical view about them.
Because the use of vaccines became widespread in the 20th century, most of us alive today in the developed world have avoided sights that were an everyday part of life for many in previous times: smallpox wounds covering a loved one’s entire body, lockjaw proceeding to complete body muscle spasms and death from tetanus, paralysis and death from polio, a painfully swollen throat and encephalitis from mumps, and the list goes on. Often those who were hit hardest by these ailments were children.
Those born in 1900 before vaccines became widely implemented in the United States had a life expectancy of 49 years. Today that number is around 79. Consider the following infection and mortality rates for diseases that are preventable with a vaccine:
- Smallpox – 30% mortality rate, 0.9 to 2.1 infection rate
- Measles – Up to 10% mortality rate, 12 to 18 infection rate
- Polio – Less than 1%, 5 to 7 infection rate
Now apply those mortality rates to the current population of the United States, estimated by the US Census to be 328.2 million.
While it’s hard to say exactly how many people every year would be infected and die from the preventable diseases listed above, just consider this: for every person infected with the seasonal flu, they spread it to between one and two people (an infection rate between 0.9 and 2.1). And on average each year, 8% of people in the US come down with the seasonal flu.
But thanks to vaccines we don’t have to worry about us or our children dying or becoming crippled and disfigured from a preventable disease. In fact, as successive generations have avoided these abysmal sufferings an increasing number of people are even taking vaccines for granted; they don’t realize how bad life can be without them.
Addressing vaccine skeptics
“Conspiracy theorists” is often used as a pejorative term to marginalize people who are somewhere on the skeptical spectrum. In fact, it’s good to be skeptical. Anytime a new scientific study or theory comes out, scientists are the first ones to be skeptical. “Anti-vaccer” is another pejorative term that’s often used to condescend people who are concerned about potential negative health implications of vaccines.
These pejorative terms are great for labeling heretics and bad for winning converts. The truth is that at first glance there are some legitimately questionable aspects to vaccines – especially for concerned parents who want the best for their kids:
- Some vaccines contain mercury, and scientists suspect mercury is an environmental risk factor for causing autism and learning disabilities
- Some vaccines involve injection of a live disease
- Vaccines can have dangerous side effects
- Not everybody needs to be vaccinated because herd immunity offers protection
What The Professionals Say
While the above statements are true, knowing their underlying complexities means you’ll have a more informed understanding about vaccine safety.
Issue #1: Some vaccines contain mercury, and scientists suspect mercury is an environmental risk factor for causing autism and learning disabilities.
It is true that some vaccines contain mercury, and scientists suspect mercury exposure is an environmental risk factor that can increase the rates of autism and learning disabilities. But here’s what else is vital to know.
The MMR (measles, mumps, rubella) vaccine, the chickenpox vaccine, the inactivated polio vaccine, and pneumococcal conjugate vaccines (vaccines against strep pneumonia) never contained mercury.
Since 2001, mercury has been removed from other vaccines intended for children. All vaccines that are routinely recommended for children six years of age and younger are available in formulations that do not contain mercury.
The most common vaccine that does contain mercury is the seasonal flu vaccine, and this is also available in formulations that do not contain mercury.
Furthermore, the danger posed by mercury depends on what chemical compound it’s in. It’s the same with alcohol. You can drink ethyl alcohol on a night out and when you wake up the next morning with a headache wonder what embarrassing things you did. If you drink methyl alcohol you’ll go blind.
For vaccines that do have mercury, the mercury is in the ingredient thimerosal. Thimerosal contains ethylmercury, and this type of mercury is broken down and readily cleared from the body; it doesn’t pose a danger of building up like the more harmful form of mercury, methylmercury.
Methylmercury poses a danger to humans in the environment. This is the type of mercury people can become sick from if they eat too much contaminated seafood. This is also the type of mercury that is linked to increased rates of autism and learning disabilities.
Ethylmercury, the kind of mercury in some vaccines, has been studied and found to have no links to autism. In some rare cases people may be allergic to ethylmercury.
Issue #2: Some vaccines involve injection of a live disease
This is true. Some vaccines like the MMR and chickenpox vaccines contain live-but-weakened (attenuated) forms of diseases that allow your immune system to recognize each and develop an antibody response with a relatively very low risk.
However, live attenuated vaccines are relatively riskier than other types of vaccines that involve dead viruses and bacteria. Therefore these are not considered safe for people with weakened immune systems or pregnant women, and aren’t recommend for infants below one year of age. On the other hand, live attenuated vaccines provide the best immune response; a lifetime of relative immunity.
There is a very very small chance of a live attenuated vaccine infecting the person who is vaccinated. This almost never happens, and the risk of this happening is far lower than the risk of actually contracting the disease if not vaccinated.
And public health officials do consider those odds very carefully. It’s for this reason that the smallpox vaccination is no longer required. Smallpox has been eliminated and therefore the potential for complications arising from the vaccine, as minuscule as they are, outweigh the virtually-zero risk of contracting it.
Other vaccines contain inactivated (dead) viruses and bacteria, their components, or their associated toxins. These include vaccines for whooping cough (pertussis), tetanus, and diphtheria. It’s impossible to become infected from these types of vaccines.
Issue #3: Vaccines can have dangerous side effects
They can, but these are rare, and the odds of becoming sick and experiencing the negative and potentially life-threatening effects of something like the measles or mumps are far higher. The same goes for the odds of being allergic to a vaccine.
Issue #4: Not everybody needs to be vaccinated because herd immunity offers protection
Herd immunity happens when so many people are immune to an infectious disease –as a result of having already contracted it and developing a natural immunity, or through immunization– that it can’t spread to others and maintain itself in a population; it’s defeated by a person’s immune system before it can establish itself in its next host.
While it is true that herd immunity offers protection for those who aren’t vaccinated, the requisite amount of people in the “herd” who must be vaccinated or immune is different for every infectious disease.
For a highly contagious disease like the measles, heard immunity requires roughly 95% of a community to be immune. Vaccines themselves are typically 95% to 99% effective, so this margin of error makes being vaccinated for measles particularly important.
Herd immunity for the seasonal flu kicks in when around 60% of the population is immune.
Current predictions for the Covid-19 pandemic –which appears to be more contagious than the seasonal flu; for every person who gets it, they infect between five and six people if preventative measures are not taken according to the most recent data– place the requisite herd immunity at at least 82%.
If you rely only on herd immunity you’re making a gamble whose odds are not in your favor, plus putting everyone else in the community at a heightened risk.
How Do Vaccines Actually Work?
Your body’s immune system can identify invading infectious diseases, develop a plan of attack, implement that plan for a successful defeat, and remember its plan of attack for later if the attacker ever returns.
Vaccines are a way of safely introducing would-be invading infectious diseases to your body’s immune system. There are four main types :
- Live attenuated (weakened) vaccines – these are weakened versions of viruses and bacteria that offer the best lifelong protection, but because they do contain live components they’re not recommended for people with diminished immune systems, such as people with HIV/AIDS.
- Inactivated vaccines – these are made from whole pieces of dead bacteria and viruses. Your body can still recognize these diseases and develop and maintain its immune response relatively effectively.
- Subunit vaccines – these are made from partial components of dead bacteria and viruses. However because these only involve partial pieces of the disease, your body’s immune system may need to be reminded about these from time to time with a booster shot.
- Toxoid vaccines – sometime it’s not the actual bacteria or virus itself that’s a problem; it’s the toxins they produce. These vaccines guard against those, but because your immune system doesn’t produce the toxin antigens itself it will need to be periodically refreshed. The tetanus vaccine is an example of this.
Vaccines have the best outcomes when everyone in the community is vaccinated. Because of the nature of individual immune systems, vaccines don’t work for between 1% and 5% of people. People with weakened immune systems who cannot receive live attenuated vaccines and those who are allergic to certain vaccines also lower the totals for a community’s level of immunity. This has implications on the level of herd immunity, underscoring why it’s important for everyone possible to be vaccinated.
How long does it take to create a vaccine?
The time it takes to develop a vaccine depends on several factors, starting with the infectious disease itself. There are no vaccines for some things that have been around for centuries like the common cold. Malaria is said to have brought down the Roman Empire but there’s still no effective vaccine for it today. In Malaria’s case, a quickly evolving parasite has thus far thwarted vaccination efforts though some trials are currently underway.
Aside from nature’s limiting factors, demand and funding also have big impacts on vaccine development. When there aren’t any quirky challenges posed by nature and there is plenty of demand, vaccines can be developed in as soon as 18 months.
There’s an intricate process of testing vaccines for safety that takes time. First it’s tested in animals, then it’s manufactured according to strict guidelines, then tested in clinical trials in humans, and once it’s approved it must be produced and distributed according to the levels of demand. Each of these steps can take months.
Some vaccines for diseases that mutate quickly must be re-released and updated. The seasonal flu vaccine is an example of this, which is re-developed twice every year. Booster shots for other types of vaccines are necessary to remind your body’s immune system to stay alert for a particular disease or to re-invigorate it with antigens, not because the infectious disease has mutated.
In the case of the Covid-19, a worldwide effort is underway to develop a vaccine that could hit the market in as soon as one year optimistically, and in 18 months more realistically. Because it’s a new virus that’s unknown to our immune systems, two inoculations will likely be needed a month apart, and ideally immunity will be conferred in about two weeks after the second.
What Vaccines Are Recommended?
Each state can establish its own vaccination requirements and instances where exemptions may be granted.
The Centers for Disease Control and Prevention (CDC) recommends vaccinations for the following diseases (many require multiple vaccinations and periodic boosters):
For infants up to six months old:
- Hepatitis B
- Whooping cough (pertussis)
- Haemophilus influenzae type b
- Polio (inactive injected)
- Flu (given at six months, and over the lifetime annually)
For children between one and two years old:
- Chicken pox
- Hepatitis A
For children between 11 and 12 years old:
- Meningococcal conjugate
For adults aged 19-26:
For adults when they turn 50: