It is well known that bacteria and viruses can become resistant to antibiotic and anti-viral drugs.
From amoxicillin for Streptococcal pneumonia infections to amantadine for the flu, resistance is a growing problem that is limiting how easily we can treat many infections.
Vaccine-Driven Resistance of Bacteria and Viruses
Since bacteria and viruses seem to have such an easy time developing resistance against commonly used drugs, do we see the same thing with vaccines?
Fortunately, no.
We do not see bacteria or viruses creating resistance in our vaccines so that they no longer work.
For example, despite what you may hear, the MMR vaccine still prevents all wild strains of measles.
What about the pertussis vaccine and the fact that we are finding more and more strains of pertactin-negative pertussis bacteria? Doesn’t that mean that the Bordetella pertussis bacteria have mutated and are causing a pertussis resurgence because they are resistant to the vaccine?
While an interesting theory, pertactin is only one of the components (antigens) of the pertussis bacteria that are in pertussis vaccines that help them to induce immunity. Others can include filamentous hemagglutinin, chemically or genetically detoxified pertussis toxin, and fimbrial-2 and fimbrial-3 antigens.
So no, pertactin-negative pertussis bacteria are not driving outbreaks of pertussis or whooping cough, and they have not become resistant to pertussis vaccines.
Vaccine-Induced Pathogen Strain Replacement
What about the fact that we sometimes seen a rise in new bacteria once a vaccine wipes out the bacteria it works against?
While this type of vaccine-induced pathogen strain or serotype replacement can happen, it is not because the bacteria develop any kind of resistance. Some vaccines can only target specific strains of a virus or bacteria. The latest version of Prevnar, for example, can prevent the 13 strains of Streptococcal pneumonia that are most likely to cause disease in children. That leaves out over 75 other strains.
And the Hib vaccine only prevents Haemophilus influenzae type b infections. There are five other H. flu serotypes (a-f) and other non-typeable strains that aren’t covered by the Hib vaccine.
The same goes for the meningococcal vaccines. None of them cover all meningococcal serotypes.
Isn’t it just as bad if one of those other strains starts growing after your kids are vaccinated?
While it certainly sounds bad, as it seems like you are just replacing one bacteria for another, it really isn’t.
Why not?
Because the replacement bacteria are often much less likely to cause invasive disease and the levels of disease they do cause don’t come anywhere close to pre-vaccine levels.
Vaccines work, even when something like vaccine-induced pathogen strain replacement happens.
Vaccines Can Help Prevent Drug Resistance
If you are really concerned about antibiotic resistance, you would want more people vaccinated.
Not only do vaccines not lead to an increase in vaccine or drug resistant bacteria or viruses, but they can help us fight the growing problem of drug resistance.
“Vaccinating humans and animals is a very effective way to stop them from getting infected and thereby preventing the need for antibiotics.”
WHO on Why is vaccination important for addressing antibiotic resistance?
Consider all of the people who take Tamiflu or antibiotics when they get the flu because they didn’t get a flu shot?
Or how many antibiotic prescriptions haven’t been written because kids did get vaccinated with Prevnar and never got an ear infection, pneumonia, or meningitis?
Vaccines in the pipeline could help even more.
What to Know About Vaccine-Driven Resistance
Vaccines are not causing an increase in vaccine-resistant bacteria or viruses and can actually help us fight the growing problem of antibiotic resistant bacteria.
More About Vaccine-Driven Resistance
- What if a vaccine kills off one strain of a disease—but makes room for another?
- A Vaccine Eliminated A Deadly Killer Of Infants. So Why Do Some People Fear It?
- CDC – Pneumococcal Vaccination: What Everyone Should Know
- WHO – Why is vaccination important for addressing antibiotic resistance?
- Vaccines are part of the solution to the emerging crisis of antibiotic resistance
- Study – Vaccines and antibiotic resistance.
- CDC – Pertactin-Negative Pertussis Strains
- Study – Pertussis Vaccine Effectiveness in the Setting of Pertactin-Deficient Pertussis
- Study – Bacterial Vaccines and Serotype Replacement: Lessons from Haemophilus influenzae and Prospects for Streptococcus pneumoniae
- Study – Vaccine-induced pathogen strain replacement: what are the mechanisms?
- Study – Did Large-Scale Vaccination Drive Changes in the Circulating Rotavirus Population in Belgium?
- Study – The rise and fall of pneumococcal serotypes carried in the PCV era
- Study – Changing epidemiology of invasive Haemophilus influenzae in Ontario, Canada: Evidence for herd effects and strain replacement due to Hib vaccination