From Covid-19 to cancer care: What are mRNA vaccines and how do they work?

mRNA vaccines made headlines during Covid-19, now they could redefine cancer treatment. Here's what Nobel Prize-winning technology is and how it works

The 2023 Nobel Prize-winning mRNA technology became a critical tool during the Covid-19 pandemic, enabling vaccines that protected millions from severe illness and death. 

But what is mRNA, and how does this cutting-edge science work?

According to the Cleveland Clinic, an American nonprofit academic medical centre, an mRNA vaccine trains your body to fight infectious diseases by delivering instructions to make a small, harmless part of the virus. This teaches the immune system how to respond if it encounters the virus again.

 

Currently, only Covid-19 vaccines use mRNA technology, but scientists are now experimenting with mRNA-based cancer treatments.

What makes mRNA vaccines different from traditional ones?

Traditional vaccines deliver a weakened or inactivated germ—or a fragment of it—to help your immune system recognise and respond to the threat.

 

 

In contrast, mRNA vaccines deliver “genetic instructions” in the form of messenger RNA. These instructions teach your cells to produce a harmless piece of the virus. The immune system then learns how to fight it. There’s no live virus involved. The production process is faster, doesn’t rely on live cultures, and is easier to adapt to new variants.

Why were mRNA vaccines a game-changer during the pandemic?

Once the coronavirus genome was decoded, scientists were able to design mRNA vaccines in just a few weeks. This speed and flexibility helped prevent countless hospitalisations and deaths. Many experts consider this one of the most significant breakthroughs in modern vaccine science.

Does mRNA alter your DNA?

According to Dr Neha Rastogi, consultant – infectious diseases, Fortis Gurgaon, the mRNA never enters the nucleus where DNA resides. “It does not integrate into human DNA and is broken down by normal cellular processes within hours to days,” she explained.

 

“Global pharmacovigilance (billions of doses) shows a strong safety profile. Rare risks, such as myocarditis—inflammation of the heart muscle, mostly seen in young males—are typically mild and resolve on their own. No credible evidence supports claims of DNA alteration,” she added.

Common side effects of mRNA vaccines

The common side effects are similar to other traditional vaccines. These include:

• Sore arm
• Fatigue
• Headache
• Low-grade fever

While there is a rare chance of myocarditis or pericarditis in young males, these are extremely uncommon. “The benefits of vaccination far outweigh these risks,” Dr Rastogi emphasised.

Beyond Covid: Can mRNA fight flu and cancer?

According to Dr Rastogi, researchers are now exploring mRNA vaccines for seasonal flu, combination shots (like flu plus Covid), and cancer.

 

“In oncology, personalised mRNA vaccines train the immune system to hunt tumours based on unique genetic mutations,” she said. However, she cautioned that mRNA is not always the best fit for every pathogen or setting.

 

“Expect a mixed toolbox—mRNA for speed and precision, and protein/subunit/live-attenuated vaccines where cost, storage, or mucosal immunity matters,” she said.

Why do some still think mRNA vaccines were rushed?

While Covid-19 did accelerate deployment, the underlying research behind mRNA vaccines had been underway for decades. The pandemic simply brought in unprecedented funding, global cooperation, and real-time data gathering.

 

“Continuous monitoring worldwide has confirmed the safety and effectiveness of mRNA vaccines for their intended use,” Dr Rastogi said.

Why is the US cutting mRNA vaccine funding?

In August 2025, the US Department of Health and Human Services (HHS) cancelled around $500 million in mRNA vaccine development under the Biomedical Advanced Research and Development Authority (BARDA). This affects 22 projects, including those for bird flu and cancer.

 

US Health Secretary Robert F. Kennedy Jr. cited doubts about mRNA’s ability to protect against upper respiratory infections. “We’re shifting that funding toward safer, broader vaccine platforms that remain effective even as viruses mutate,” he said in an HHS statement.

 

Public health experts are alarmed, warning that the decision could threaten pandemic preparedness, derail cancer research, and hurt US biotech leadership.

 

“No credible epidemiologic signal shows a vaccine-driven surge in aggressive cancers,” Dr Rastogi said. “Surveillance has not identified a causal link between mRNA Covid-19 vaccines and increased cancer risk.”

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This content is for informational purposes only and is not a substitute for professional medical advice.