His own FMLA leave became the basis for the review that cost him his job
A scientist who helped build Moderna's COVID-19 vaccine alleges the company used his mental health leave against him - then fired him.
The lawsuit, filed October 27, 2026, in the US District Court for the Eastern District of Pennsylvania, claims Moderna gave the worker a negative performance review based on quarters when he was either experiencing a mental health crisis or on approved leave. It then used that review to pull an internal transfer and terminate him in a single morning.
According to the complaint, the worker spent twelve years at Moderna, joining in April 2014 as a scientist and earning four promotions to reach director level. The filing describes him as a patent inventor, team leader, and expert in lipid nanoparticle technology - work that, according to the complaint, fed directly into the development and manufacturing scale-up of Moderna's COVID-19 vaccine.
Moderna publicly celebrated those contributions. The complaint states the company featured the worker in media coverage during the pandemic, including a 2020 New York Magazine profile. According to the filing, Moderna's CEO called the worker the company's "MacGyver."
His former supervisor - described in the complaint as the head of global research and development for Moderna's lipid nanoparticle platform - called his expertise "worldclass" in a recommendation letter attached to the filing. That March 2026 letter described him as "a role model for the company's values" and "a role model for scientific innovation."
Then things fell apart.
The complaint alleges the years of intensive work - days, nights, weekends, missed parental leave when his daughter was born - took a severe toll. In the first quarter of 2025, according to the filing, the worker suffered a breakdown at work. His treating psychiatrist diagnosed him with Major Depressive Disorder and advised him to take time off.
Moderna approved the leave. The complaint states the worker took approximately three and a half months of FMLA and short-term disability leave starting May 16, 2025, during which he took part in an intensive outpatient program.
He came back in early September 2025. His new supervisor praised his fourth-quarter performance as "strong," according to the filing. But in early March 2026, that same supervisor rated his overall 2025 performance as "inconsistent" - the first negative review of his career.
The basis, the complaint alleges, was the first and second quarters of 2025. During the first, the worker was in the grip of a mental health crisis. During the second, he was on approved FMLA leave.
What happened next moved fast.
The complaint alleges the worker had already been approved for a transfer from his director-level position in product development to Moderna's digital AI team. According to the filing, the move was signed off by four senior leaders, and the worker spent about four weeks on the new team, including building a "Freedom-to-Operate Analysis" tool for Moderna's legal department that drew praise as "remarkable" work.
On the morning of March 12, 2026, according to the complaint, an HR business partner for the digital team called to say the transfer was being rescinded because of the "inconsistent" rating.
About thirty minutes later, the complaint alleges, the worker's former supervisor and an HR business partner from his old team called to say his previous position had been eliminated - because he had already transferred out of it.
The complaint describes a catch-22: the worker could not stay in the new role because of the performance rating, and could not go back to his old role because it no longer existed.
He was terminated that same day, with an effective date of March 27, 2026, according to the filing. The complaint alleges Moderna immediately cut off his computer access, barred him from its facilities, and gave him no chance to speak with colleagues.
The worker filed a charge of discrimination with the EEOC on April 22, 2026, and received a right-to-sue letter on September 1, 2026, according to the complaint. The lawsuit brings two counts: disability discrimination under the Americans with Disabilities Act, and retaliation under the Family and Medical Leave Act, which protects employees who take approved medical leave from being penalised for doing so.
The complaint seeks back pay, front pay, compensatory and punitive damages, and attorney fees. It also flags that the worker plans to add a claim under Pennsylvania's state anti-discrimination law.
According to the filing, the loss of unvested stock alone has cost the worker millions of dollars. The complaint points to an August 19, 2026, announcement by Moderna and Merck regarding a melanoma therapy that, the filing states, caused Moderna's stock to triple - a therapy the worker alleges he helped develop during his time at the company.
For HR teams, the case raises a sharp practical question: when an employee takes protected medical leave, can the months they were absent be counted against them in a performance review - and can that review then be used to justify a termination?
The allegations in the complaint have not been tested in court, and no findings have been made on any of the claims.
