A "one-size-fits-all" approach to lockdown may not have been as effective in black, Asian and minority ethnic (BAME) communities, scientists claim.
A study of Covid-19 in Leicester found cases continued to rise in BAME groups in the city in the three weeks that followed the 23 March lockdown.
In contrast, rates in white groups "dropped off very sharply".
Researchers said the findings raise "serious questions" on whether lockdown is effective for a diverse population.
Dr Manish Pareek - a professor in infectious diseases at the University of Leicester - studied patients admitted to the University Hospitals of Leicester NHS Trust.
He and his team found the proportion of people from BAME groups who tested positive for coronavirus continued to rise, peaking at 50.9% in the initial weeks of the full restrictions.
The figure for people from white backgrounds remained between 24% and 26%.
Dr Pareek said there were a number of factors that could potentially explain their findings.
These include working in front-facing roles, living arrangements and difficulties communicating public health messages when there is a language and cultural barrier.
Dr Pareek said: "At the moment, there is perhaps a one-size-fits-all approach.
"Obviously, lockdown has had a huge impact in reducing infection rates but the question is, is it enough for certain parts of the country?"
He suggests preparing for future waves with a tailored public health messaging aimed at specific BAME groups.
Leicester is currently the only city in England following stricter lockdown measures.