Still Talking About the mRNA COVID Vaccine? Us Too—and Here’s Why

We first started talking about the COVID-19 vaccine five years ago. And somehow, here we are—still talking about it. Still answering patient questions, still sorting through the latest data, and still trying to find the right words when the topic comes up in the exam room.

Honestly? It’s not always easy. When a patient asks, “Do I really need another COVID shot?” it can stir up some of our own uncertainty. The science keeps evolving, and even clinicians can struggle to keep up. There’s always that quiet fear that we don’t have all the answers.

But we know more now than we did in 2020. A lot more. And this fall and winter—with COVID, flu, and RSV circulating—we’ve got updated vaccines and new evidence that helps us answer those tough questions with confidence. Let’s walk through what we know today about mRNA vaccines: how they work, how well they protect, what we’ve learned about long COVID, and what the safety data really shows.

mRNA Vaccines: The snapchat of mmunology

The COVID-19 vaccines from Pfizer and Moderna are made with messenger RNA—basically a temporary instruction manual that tells your muscle cells to make the spike protein found on the virus’s surface. That protein triggers your immune system to respond and build protection.

For patients still worried about the idea of mRNA being injected into their body, here’s a helpful metaphor: it’s like Snapchat. The mRNA delivers its message and disappears. It never enters the cell’s nucleus (where DNA lives) and has no effect on your genetic material. Within weeks, it’s broken down by RNase into ribonucleotides.

Are the COVID-19 vaccines still effective?

Yes—especially for older adults and high-risk patients. A study published in JAMA in July 2025 estimated that COVID-19 vaccines saved over 2.5 million lives globally between the start of vaccine rollout and October 2024. Nine out of ten of those lives saved were among people over age 60.

A 2023 meta-analysis of real-world vaccine data from 2020 to 2022 showed the mRNA vaccines have remained effective during the Omicron era, although it’s important to note that people require three doses of the vaccine  Three doses of mRNA COVID-19 vaccine  reduced the risk of infection by 60%, symptomatic infection by 57%, and severe disease by 87%. 

That protection persists for at least three months, though it tends to wane by the six-month mark. Annual boosters are important to protect patients through peak respiratory virus season.

Do vaccines protect against long COVID?

This is a question we hear more often now and the data, while still evolving, points in a hopeful direction. A systematic review from 2025 concluded that COVID vaccinations likely reduce the risk of long-COVID in most people. Furthermore, a 2024 article in The New England Journal of Medicine attributed about 70% of the decrease in long-COVID rates to vaccination, particularly as the Omicron variant became dominant.

Long-COVID is a tricky thing to study, because the symptoms are vague, but it continues to be a major concern for both clinicians and patients. The working theory is that by reducing viral persistence and illness severity, the vaccine lowers long-COVID risk. We still have much to learn, but I feel comfortable telling patients the data look promising.

Let’s talk safety

One of the most common myths we still hear is that mRNA vaccines are “too new.” But the truth is, they’ve been studied since the 1960s and intensively researched since the ’90s. And now that they’ve been given to hundreds of millions of people, we have an extraordinary amount of safety data.

Here’s what that data show:

• A 2023 study of more than 3 million adults over 65 found no increased risk of serious events like myocardial infarction, Bell’s palsy, pulmonary embolism, or myocarditis after COVID-19 vaccination.
  
  
• A 2025 study in Denmark followed over a million high-risk individuals who received the updated JN.1 vaccine during the 2024-2025 season. It found no increased risk of 29 adverse events in the 28 days after vaccination.
  
  

It’s worth acknowledging that younger people—especially males ages 16 to 29—do have a small increased risk of myocarditis or pericarditis, especially after the second dose. (A total of 411 cases of myocarditis or pericarditis were observed out of more than 15 million people aged 18-64 who received the vaccine.) Even then, the risk of myocarditis from COVID infection is higher than from vaccination.

Are there frequent side effects? Yes, patients may feel fatigued, feverish, or achy after the shot. That’s normal—and self-limited. These symptoms usually resolve within 1–2 days, though they can occasionally linger for up to a week. It can help to explain to patients that these symptoms are a sign that their immune system is working, but it’s also important to validate those experiences. If we downplay how lousy someone feels, we may lose their trust when we try to reassure them about safety overall.

When the data are analyzed, the benefits of the COVID-19 vaccine outweigh the risks for nearly everyone; however, we should acknowledge that benefit is highest for people over age 65 with at least 1 risk factor, and lowest for healthy teenage boys.

What to say in the exam room this fall

Here’s what I’m telling my patients this season:

• The vaccine is safe and effective, especially for older adults and people with chronic conditions.

• It helps prevent severe disease, hospitalization, and death, but make sure you’ve had at least 3 doses.

• The vaccine may also reduce the risk of long-COVID.

• Protection wanes after 3 to 6 months, so timing matters—fall is the right time to get boosted.

• Mild side effects are common; serious ones are extremely rare.

I’ll be honest: I’ve sometimes given up when patients seemed resistant. I’ve nodded politely and moved on. But when it comes to my high-risk patients, I’m re-engaging. Because the updated 2025–2026 COVID vaccine isn’t just another shot. It’s a tool that could save lives this winter.

And isn’t that worth talking about?

If you want to hear more, listen to our Primary Care Reviews and Perspectives podcast episode, "COVID Vaccine Updates."