Topics:
- COVID-19
- Flu & Cold
- Lung Health & Procedures
- Pneumonia
Every year, millions of Americans deal with the effects of respiratory illnesses. While many infections start with seemingly mild symptoms like a cough, fever, runny nose or sore throat, they can sometimes develop into something much more serious: pneumonia
It doesn’t always receive the same attention as the flu, COVID-19, RSV or measles, but pneumonia can be serious and even life threatening, causing over 1.4 million emergency room visits and more than 40,000 deaths in the U.S. every year. In many cases, pneumonia develops as a complication from other respiratory infections
Fortunately, vaccines are very effective in reducing the risk of both respiratory infections and the severe complications that can follow, including pneumonia. Recent efforts to change federal vaccination recommendations and misinformation in the media have caused confusion and uncertainty. But experts agree that staying up to date on recommended vaccinations is the best way to protect yourself, your family and your communities from serious illness
“It is a huge success of our society to offer vaccine access,” observed Caytlin Deering, DO, FACP, Infectious Disease Physician at Metro Infectious Disease Consultants. “Loss of access and halting education regarding vaccines poses an enormous health risk.”
Why Pneumonia Remains a Serious Public Health Threat
Many people think of pneumonia as a standalone illness, but it often develops as a secondary complication from another respiratory infection. “Infections like measles and flu cause pneumonia when the virus affects the lung tissues, causing inflammation as a result of the infectious agent,” Dr. Deering explained. When that happens, bacteria and other pathogens have an easier time causing a serious lung infection
“While not every person that contracts flu or measles 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.”
People who are at increased risk for pneumonia include:
- Infants and young children
- People with chronic lung disease like asthma or chronic obstructive pulmonary disease (COPD)
- Individuals with weakened immune systems
- People living with chronic medical conditions such as heart disease or diabetes
For these populations, preventing respiratory infections can be critical to avoiding hospitalization, respiratory failure and even death
The Current Landscape: The Dangerous Decline of Childhood Vaccination Rates
With today’s endless information streams, many people forget that vaccines have dramatically reduced the burden of infectious diseases over the past several decades. “We have been very fortunate over the last 40+ years in the U.S. to have seen less and less vaccine-preventable illnesses and the complications they bring,” said Dr. Deering. “Most adults in their early 30s never even contracted varicella (chickenpox)! While polio, diphtheria, measles, mumps were all infections that many children contracted (in the past), the long-term effects aren’t often seen today because of vaccines.”
Unfortunately, doctors and health experts have become increasingly concerned about recent declining vaccination rates. According to Centers for Disease Control and Prevention (CDC), the MMR (measles, 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 the 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. Individuals with weakened immune systems due to aging, treatments or medical conditions as well as infants and young children who have not completed their immunization schedules are also at risk.
As of the 2025 school year, about 286,000 kindergarteners lacked documentation of a completed MMR vaccine series and that number has only increased. Lower vaccination rates have important implications as they increase the chances of highly contagious diseases such as measles spreading within communities. “Due to the infectivity of the measles 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.”
Vaccines that Help Prevent Respiratory Illnesses and Pneumonia
Measles and the MMR Vaccine (Measles, Mumps, and Rubella)
Measles is more than just a childhood illness that causes fever and a rash. It also commonly infects the respiratory tract before spreading throughout the body. Since measles suppresses the immune system, infected individuals become more vulnerable to dangerous secondary infections, pneumonia included. In fact, 1 in 20 children with measles develop pneumonia and it is the most common cause of measles-related deaths
“The measles 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 from other viruses they may have previously contracted and overcome.”
As measles is one of the most contagious infectious diseases in the world, the best way to protect against severe complications is to get vaccinated. The CDC reports that one dose of the MMR vaccine is about 93% effective against measles, 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 virus that causes measles is extremely contagious,” agreed Dr. Deering. “It is spread by aerosolized droplets, and infectious particles can remain in the air for several hours, making isolation in the early stages especially difficult (prior to diagnosis or suspicion of diagnosis).”
The Importance of Flu Shots
On average, 8% of Americans get the flu every year, resulting in 6,300 to 52,000 flu-related deaths. One of the most serious flu-related complications is pneumonia, which can be caused in two ways. Either the virus itself directly infects the lungs and causes viral pneumonia or it weakens the body’s immune defenses, making secondary bacterial pneumonia more likely
Choosing to receive an annual flu vaccine is the best way to protect from severe illness, hospitalization, and complications. Because the flu is constantly changing and adapting, it is recommended to receive a flu shot annually. Due to the virus’ unpredictability, flu vaccination currently cannot prevent all flu illnesses. “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,” remarked Dr. Deering.
COVID-19, RSV, Whooping Cough and Pneumococcal Disease Can Cause Pneumonia
All four of these diseases have immunizations available to help reduce the risk of pneumonia. 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. COVID-19 can cause severe inflammation and fluid buildup in alveoli, the tiny air sacs in the lungs where oxygen exchange, leading to severe pneumonia, breathing difficulties and even respiratory failure. This is why CDC continues to recommend vaccination which help protect against hospitalization, critical illness and death
RSV is another common respiratory infection that can lead to pneumonia, particularly in young children and older adults. tLast respiratory virus season, CDC estimates there were 170,000-340,000 RSV-related hospitalizations. While most people experience mild symptoms, some develop serious illness. The best way to prevent severe illness, including pneumonia, is immunization for eligible individuals. “Young children are often vulnerable to respiratory infections due to limited exposures to infections and not having yet met the age for appropriate vaccinations,” agreed Dr. Deering. RSV immunizations have shown to be effective at preventing emergency department visits and hospitalizations.
Pertussis, or whooping cough, can also cause pneumonia, one of its most common complications. Infants are particularly vulnerable because their immune systems are still developing and they may be too young to be fully vaccinated. DTaP and Tdap vaccines remain the most effective tools for reducing the risk of severe disease and helping protect infants and other vulnerable populations
Why Vaccines Matter Even if Infection Occurs
Although these illnesses differ in how they spread and who they affect most, they share an important connection: each has the potential to develop into pneumonia and cause hospitalization, long-term health complications and even death. Vaccination helps reduce the risk of infection and, just as importantly, lower the likelihood that an infection will progress to severe disease and pneumonia. “Long term complications from infections, while not common, can change a child and family’s life dramatically,” noted Dr. Deering. “By exposing the child’s immune system to a vaccine, the body forms antibodies, as if they have seen and fought the virus itself. The vaccine is a controlled amount, however, and side effects that are experienced are typically mild.”
Many people assume a vaccine has failed if they still get sick, but this is a common misconception. Vaccines are designed to help your immune system respond more effectively when exposure happens, reducing the chances that a respiratory illness becomes severe. In many cases, vaccination can reduce the severity of illness, turning potentially serious disease into a milder, more manageable infection
Perhaps most importantly, vaccination helps protect not only individuals but entire communities. When more people are vaccinated, there are fewer opportunities for dangerous viruses and bacteria to spread to those at highest risk. For many families, staying up to date on recommended vaccines is a simple step that can help prevent severe illness, reduce the risk of complications like pneumonia, and protect their health throughout respiratory virus season
Protect Yourself Before Respiratory Virus Season Arrives
When it comes to respiratory illness and pneumonia, prevention is most effective before infection occurs. Vaccination can help reduce the risk of illness and protect against serious complications
Before respiratory virus season arrives, make sure you and your family are up to date on recommended vaccinations by talking with your healthcare provider about which vaccines may be appropriate based on age, medical history and risk factors. “I suggest asking your healthcare provider: ‘What the recommended vaccines are for my child at this age, what is the timeline for each, and what are the risks of not being vaccinated?’” Many healthcare plans cover recommended vaccines with no out-of-pocket costs. Be sure to check with your insurance provider for coverage details. Vaccines can often be received at your doctor’s office, pharmacy, or local health department.
Learn more by visiting Lung.org/viruses
Blog last updated: August 27, 2026
