Tag: immunity

Waning Immunity and Vaccines

How long does immunity last after you get vaccinated?

Protection from most vaccines lasts a long time.

While we are detecting waning immunity, or protection that wears off sooner than expected for some vaccines, most provide long-lasting, even lifetime protection.

Waning immunity is a problem for the mumps and acellular pertussis vaccines.

We have also always known that tetanus requires regular boosters for good protection and that you need to get a flu vaccine each and every year, even when flu strains in the vaccine don’t.

Immunity from most other vaccines lasts a long time and doesn’t wane or decrease over time.

For More Information On Waning Immunity:

Effectiveness Rates of Vaccines

We know that vaccines work.

But how well do they work?

Taken together, you have to say that vaccines work very well.

Remember, according to the CDC:

Vaccine efficacy/effectiveness (VE) is measured by calculating the risk of disease among vaccinated and unvaccinated persons and determining the percentage reduction in risk of disease among vaccinated persons relative to unvaccinated persons. The greater the percentage reduction of illness in the vaccinated group, the greater the vaccine efficacy/effectiveness.

They aren’t perfect though and some vaccines do work better than others.

For example, the MMR vaccine provides 99% protection (two doses) against measles, while the seasonal flu vaccine can vary from 10% to 60%, depending  on how well the flu vaccine matches the flu virus strains that are getting people sick that year.

Fortunately, most vaccines have over 90 to 95% effectiveness.

The exceptions, in addition to flu vaccines, are the mumps and pertussis vaccines.

In addition to problems with waning immunity, they have lower rates of effectiveness than most other vaccines:

That’s probably why we are seeing more outbreaks of mumps and pertussis among vaccinated children and young adults, although intentionally unvaccinated children and adults are also contributing to most of those outbreaks.

For More Information On Efficacy Rates of Vaccines:

Quarantines for Vaccine Preventable Diseases

The “quarantine of susceptible contacts without presumptive evidence of immunity” is a key tool that health experts use to control outbreaks of vaccine-preventable diseases.

Some examples of quarantine periods include:

  • 10 days for healthy dogs and cats after a bite (rabies)
  • 21 days for measles
  • 21 days for chicken pox

In addition to susceptible contacts, during an outbreak, even those who aren’t contacts are sometimes put under quarantine, or at least restricted from going to school, if they aren’t naturally immune and haven’t been vaccinated.

This is especially common during outbreaks of measles and chicken pox and in which case the quarantine may last much longer than 21 days. In general, unvaccinated kids will have to stay out of school for at least 21 days after the last person was no longer contagious.

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Natural Immunity

Is natural immunity – the kind of immunity you get from actually getting a disease – better than immunity from a vaccine?

All things being equal, sure.

Unfortunately, all things aren’t equal when it comes to the question of natural immunity vs ‘artificial’ immunity. Vaccines are safe and have few serious side effects, while vaccine-preventable diseases are life-threatening and can leave survivors with serious disabilities.

For most of us there is no question. Our kids are fully vaccinated and we are very glad that they have artificial immunity against measles, Hib, pneumococcal disease, and hepatitis B, etc.

And people shouldn’t get confused about natural immunity. It doesn’t mean that you just wake up one day have immunity against a disease one day naturally. You have to earn that immunity, by getting sick with the disease and hoping you don’t have any complications, some of which can be life-threatening.

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Herd Immunity

Herd immunity or community immunity refers to the process in which all people are protected against a vaccine-preventable disease because most of the community is vaccinated.

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