Are older people protected against measles? Here's what seniors and caregivers need to know

According to the Centers for Disease Control and Prevention (CDC), before the vaccine era, nearly every person was infected with measles by the age of 15. In this context, the question arises: are older people protected against measles today, especially those who lived through the pre-vaccine era?

Quick Summary

Immunity to measles in older adults depends on their birth year and vaccination history; those born before 1957 are generally presumed to be immune due to natural infection, while those born later may need documentation of vaccination or immunity. It is crucial to understand individual risk factors, especially given recent measles outbreaks, and consult a healthcare provider for personalized advice.

Key Points

• Presumptive Immunity for Pre-1957 Births: Individuals born before 1957 are generally considered protected against measles due to likely exposure and natural immunity during childhood, though healthcare workers are an exception.

• Variable Immunity for Post-1957 Births: For those born after 1957, immunity depends on vaccination history, with two doses of the MMR vaccine providing lifelong protection for most.

• Outdated Vaccines and Boosters: People who received an inactivated measles vaccine between 1963 and 1967 should be re-vaccinated, as that version was less effective.

• Risk of Serious Complications for Seniors: Older adults are at increased risk for severe measles complications like pneumonia and encephalitis, especially with underlying health conditions or weakened immune systems.

• Immune Amnesia Threat: A measles infection can cause 'immune amnesia,' potentially erasing the immune system's memory of other pathogens, leaving seniors vulnerable to other infections.

• What to Do if Unsure: If an older adult's immunity status is unclear, they should consult a healthcare provider for a titer test or simply get the MMR vaccine again, as it is safe to do so.

Understanding measles protection across generations

Historically, measles was a common childhood illness, and most people who contracted it developed lifelong immunity. However, the introduction of the measles vaccine changed the landscape of public health, creating different immunity profiles across various age groups. For older adults, understanding their specific risk and protection level is crucial, especially with recent resurgences of the virus in some communities.

The birth year benchmark: Born before 1957

For most people born in the United States before 1957, the CDC assumes they are immune to measles. This is because the virus was so widespread during that time that virtually everyone was exposed and developed natural, lifelong immunity from the infection itself. For most older adults, this natural immunity provides robust protection. However, there are some important exceptions and nuances to this presumption:

• Healthcare personnel: This group, regardless of birth year, should have documented evidence of immunity, typically through a blood test (titer) or two doses of the MMR vaccine. Working in a healthcare setting poses a higher risk of exposure.
• Other high-risk individuals: Those who travel internationally frequently, or those who have had close contact with a measles patient during an outbreak, may need to re-evaluate their immunity status with a healthcare provider, even if born before 1957.

The post-1957 cohort: Vaccination is key

For older adults born in 1957 or later, protection is generally based on vaccination history. The MMR (measles, mumps, rubella) vaccine was introduced in 1963, and the standard two-dose schedule was not implemented until 1989. This creates varying levels of protection for different age ranges within this group. Several scenarios may apply:

• Two documented doses: Adults who received two doses of the MMR vaccine are considered protected for life and do not need a booster.
• One documented dose: Many adults who received only one dose may still be considered protected, but health experts may recommend a second dose for certain groups, such as international travelers or healthcare workers.
• Vaccinated between 1963 and 1967: The vaccine used during this period was a less effective inactivated version. People in this group should assume they are not immune and need a modern MMR vaccine.
• Uncertain vaccination history: If an adult is unsure of their vaccination status and does not have a confirmed history of measles disease, a blood test (titer) can confirm immunity, or they can simply get the vaccine again. There is no harm in receiving an extra dose of the MMR vaccine.

The threat of immune amnesia

A recent and concerning finding is the concept of "immune amnesia" caused by the measles virus. Studies have shown that a measles infection can temporarily wipe out the immune system's memory of other previously encountered pathogens. While the immune system generally recovers, this can leave older adults, especially those with already weakening immune systems, vulnerable to other infections they were once protected against. The measles vaccine protects against this devastating side effect.

Factors increasing measles risk in older adults

Beyond birth year and vaccination history, several factors can increase an older adult's risk of contracting measles and developing serious complications. These include:

• Weakened immune system: Immunosenescence, the natural decline of the immune system with age, makes it harder to fight off infections. Chronic conditions common in seniors, such as diabetes and heart disease, can also compromise the immune system further.
• Recent international travel: Measles is still common in many parts of the world. Travelers to these areas who are not confirmed immune are at higher risk.
• Close contact during an outbreak: Exposure to the virus during a local outbreak, especially in a household or community setting, can pose a risk to anyone without adequate immunity.

When is vaccination recommended for older adults?

The decision to vaccinate should be made in consultation with a healthcare provider. However, clear recommendations exist for certain scenarios:

1. If born in 1957 or later and without evidence of immunity: A single dose of MMR is typically recommended.
2. Special risk groups: Two doses are advised for healthcare personnel, international travelers, and students at post-high school institutions.
3. During an outbreak: Health authorities may recommend vaccination for any adult at increased risk of exposure, even if they have some evidence of prior immunity.

Taking action: A simple guide

Caregivers and seniors should approach measles protection proactively. The first step is to review personal medical history and vaccination records. If those are unavailable or unclear, speaking with a healthcare provider is essential. A simple blood test can clarify immunity status. Ultimately, vaccination is the most reliable way to prevent infection and severe complications. It is a powerful tool for safeguarding not just personal health, but also the health of vulnerable members of the community, such as infants too young to be vaccinated.

Natural immunity vs. vaccine-induced immunity

Feature	Natural Immunity (Post-infection)	Vaccine-Induced Immunity
Mechanism	Develops after contracting and recovering from the wild measles virus.	Develops after receiving one or two doses of the live-attenuated MMR vaccine.
Safety	High risk of severe illness and life-threatening complications (e.g., pneumonia, encephalitis) during infection.	Safe and effective with rare, typically mild, side effects. Significantly reduces the risk of severe illness and long-term complications.
Longevity	Considered lifelong for those who had the disease in the pre-vaccine era.	Highly durable, providing lifelong protection for most people who receive two doses. Some studies show a slight waning over decades, but protection remains very high.
Immune Memory	Confers robust, long-lasting immunity, but the infection can cause 'immune amnesia,' potentially erasing memory of other past infections.	Builds a safe and specific immune response without the risk of disease or the long-term immunosuppressive effects associated with natural infection.
Population Effect	Protection of individuals occurs only through mass infection, which causes significant morbidity and mortality across the population.	Achieves herd immunity, protecting both vaccinated individuals and vulnerable populations who cannot receive the vaccine.

What to do if you're concerned about measles protection

1. Check your records: Search for immunization records, especially if you were born after 1957. A written record is the most reliable proof of vaccination.
2. Consult a doctor: Discuss your history and risk factors with a healthcare provider. They can help you determine if you need a titer test or vaccination.
3. Get vaccinated: If there is any doubt about your immunity, a doctor will likely recommend the MMR vaccine. It is safe and effective, even if you are already immune, and provides peace of mind.
4. Stay informed: Keep up to date on current measles outbreaks in your area and anywhere you plan to travel. The CDC website provides current health notices.

Conclusion: Proactive steps ensure protection

While many older adults have natural immunity from past measles infections, relying solely on age as an indicator of protection can be risky. Factors like being a healthcare worker, born between 1957 and 1989, or receiving an outdated vaccine can leave some seniors vulnerable. With recent resurgences of measles, being proactive about immunity status is critical. A simple conversation with a healthcare provider can clarify individual needs and ensure the best protection for senior health and community well-being. The MMR vaccine is a safe and effective way to secure protection and avoid serious complications, including the concerning phenomenon of immune amnesia associated with natural infection. Protecting ourselves protects us all. For further information and guidelines, the Centers for Disease Control and Prevention is an excellent resource, especially for travelers and high-risk groups.

Frequently Asked Questions

Can older adults get measles if they were never vaccinated?

Yes, it is possible for older adults to get measles if they were never vaccinated. The presumption of immunity for those born before 1957 assumes widespread exposure, but it is not 100% guaranteed for every individual. If an adult born after 1957 is unvaccinated, they are susceptible and should be vaccinated.

Is natural immunity from childhood better than vaccine-induced immunity?

While natural infection typically results in lifelong immunity, it comes with a high risk of serious complications, hospitalization, and even death. In contrast, vaccine-induced immunity is highly effective and significantly safer, preventing severe disease and the dangerous side effect of immune amnesia associated with natural infection.

Should healthcare workers who are older still get vaccinated against measles?

Yes. Healthcare personnel, regardless of their birth year, should have documented evidence of immunity to measles, which is defined as two doses of MMR vaccine, a positive titer test, or laboratory confirmation of prior disease. Because of their higher risk of exposure, the CDC does not apply the "born before 1957" presumption to healthcare workers.

Can an older adult receive a measles booster if they are unsure of their status?

Yes. It is safe for an older adult to receive the MMR vaccine even if they are already immune, so getting a booster is an excellent option if vaccination records are unavailable. A healthcare provider can also perform a blood test (titer) to check for evidence of immunity.

What are the risks of measles for adults over 20?

Adults over 20 who contract measles are at a higher risk of complications than younger children. These can include pneumonia, encephalitis (brain swelling), hospitalization, and, in severe cases, death. The risk is even higher for individuals with weakened immune systems.

How can I check if I have immunity to measles?

There are three main ways to check for immunity: 1) Find written documentation of receiving one or two doses of a live measles vaccine. 2) Obtain a blood test (titer) from your doctor to confirm the presence of measles antibodies. 3) If you were born before 1957, you are presumed to be immune, but a titer test is the most definitive confirmation.

What is 'immune amnesia' and how does measles cause it?

Immune amnesia is a condition where a measles infection suppresses and resets parts of the immune system, effectively wiping out the body's memory of other pathogens. This can leave an individual temporarily vulnerable to other infections they were previously immune to, such as influenza or pneumonia, even after recovering from measles.