Declining Childhood Vaccination Rates Drive Resurgence of Measles and Pneumonia Risk
核心洞察
Pneumonia (搜索) causes over 1.4 million emergency room visits and more than 40,000 deaths in the U.S. annually, often developing as a complication of other respiratory infections.
MMR vaccination coverage among U.S. kindergarteners fell to 92.4% during the 2025-26 school year, below the 95% threshold needed for community protection.
Measles (搜索) suppresses the immune system, with 1 in 20 infected children developing pneumonia (搜索), the most common cause of measles-related deaths.
Pneumonia (搜索) causes over 1.4 million emergency room visits and more than 40,000 deaths in the United States every year, yet it often develops not as a standalone illness but as a secondary complication of other respiratory infections. As childhood vaccination rates decline, public health experts are raising alarms about the resurgence of vaccine-preventable diseases such as measles (搜索) and the heightened risk of severe complications, including pneumonia.
"Infections like measles (搜索) and flu cause pneumonia (搜索) when the virus affects the lung tissues, causing inflammation as a result of the infectious agent," explained Caytlin Deering, DO, FACP, Infectious Disease Physician at Metro Infectious Disease Consultants. "It is a huge success of our society to offer vaccine access. Loss of access and halting education regarding vaccines poses an enormous health risk."
Why Pneumonia Remains a Serious Public Health Threat
Pneumonia (搜索) frequently arises when a respiratory virus inflames lung tissue, creating conditions that allow bacteria and other pathogens to establish a serious lung infection. "While not every person that contracts flu or measles (搜索) will develop pneumonia, as both affect the respiratory system, complications such as lung inflammation, fluid buildup in the lungs, and difficulty breathing can occur, especially in people with underlying lung conditions or those that are predisposed to infections due to decreased immune system function," Dr. Deering noted.
Populations at increased risk for pneumonia (搜索) include infants and young children, people with chronic lung disease such as asthma or chronic obstructive pulmonary disease (COPD), individuals with weakened immune systems, and people living with chronic medical conditions such as heart disease or diabetes. For these groups, preventing respiratory infections can be critical to avoiding hospitalization, respiratory failure, and even death.
The Dangerous Decline of Childhood Vaccination Rates
According to the Centers for Disease Control and Prevention (搜索) (CDC), MMR (measles (搜索), mumps, and rubella) vaccination coverage fell to 92.4% among U.S. kindergarteners during the 2025-26 school year, dropping below the 95% threshold considered important for community protection against outbreaks. Currently, only 10 states maintain MMR coverage above 95%, which has led to a spike in measles cases in multiple states and has the U.S. reporting the highest number of cases since the disease was considered eliminated in 2000.
"When vaccine rates decline, multiple groups are at increased risk. This includes not just the unvaccinated individuals themselves, but also those that cannot be vaccinated due to allergy or contraindication," Dr. Deering continued. As of the 2025 school year, about 286,000 kindergarteners lacked documentation of a completed MMR vaccine series, a number that has only increased.
Measles and the Immune System
Measles (搜索) is more than a childhood illness causing fever and rash; it commonly infects the respiratory tract before spreading throughout the body. Because measles suppresses the immune system, infected individuals become more vulnerable to dangerous secondary infections, including pneumonia (搜索). In fact, 1 in 20 children with measles develop pneumonia, and it is the most common cause of measles-related deaths.
"The measles (搜索) virus is unique in that it destroys the memories of the immune system cells. So, while a person may survive and now have antibodies for that specific virus, they have become increasingly susceptible to other infections. It's like hitting 'reset' on the immune system," Dr. Deering explained. "This increases their risk of developing severe respiratory infections and pneumonia (搜索) from other viruses they may have previously contracted and overcome."
The CDC reports that one dose of the MMR vaccine is about 93% effective against measles (搜索), while two doses are about 97% effective. About 1 in 5 unvaccinated people who get measles will require hospitalization, and the most recent U.S. outbreaks have occurred primarily in under-vaccinated communities.
The Role of Flu and Other Vaccines
On average, 8% of Americans get the flu every year, resulting in 6,300 to 52,000 flu-related deaths. Pneumonia (搜索) is one of the most serious flu-related complications, arising either when the virus directly infects the lungs to cause viral pneumonia or when it weakens the body's immune defenses, making secondary bacterial pneumonia more likely.
"While the flu vaccine does not guarantee prevention of an infection (largely due to the virus having small changes called antigenic drift), being vaccinated reduces the risk of developing a severe flu related complication," Dr. Deering remarked.
Beyond measles (搜索) and flu, COVID-19, RSV, whooping cough (pertussis), and pneumococcal disease can all cause pneumonia (搜索). The pneumococcal vaccine directly protects against pneumococcal pneumonia, the leading cause of bacterial pneumonia, while COVID-19, RSV, and DTaP/Tdap vaccines help prevent infections that can lead to pneumonia and other serious respiratory complications. Although COVID-19 rates have decreased since the pandemic, it still contributes to around 47,000 deaths annually. Last respiratory virus season, the CDC estimated there were 170,000-340,000 RSV-related hospitalizations.
Policy Context and Public Support
On August 10, 2026, President Trump issued an executive order directing changes to federal childhood vaccine recommendations. However, the order does not change New York State's school vaccination policies, which remain in effect. Public opinion polls indicate that most Americans, regardless of political affiliation, support the continued availability of FDA-approved vaccines, with 89% of people saying vaccines are essential for public health.
Experts emphasize that staying up to date on recommended vaccinations remains the best way to protect individuals, families, and communities from serious illness. "Due to the infectivity of the measles (搜索) virus, when someone is infected, those unvaccinated individuals will also likely contract the infection. Individuals that would have been protected (because those around them had immunity), are now at significantly increased risk of contracting the virus as well," Dr. Deering concluded.