Home Office data shows 32 cases were recorded by Lewes prison between March 2020 and the end of January.
But charity the Prison Reform Trust said measures introduced to reduce the spread of the virus in custody, such as keeping prisoners in their cells for most of the day, have taken a ‘significant’ mental and emotional toll on inmates nationally.
January saw the highest number of infections among prisoners, when 25 people tested positive.
At the start of the pandemic, not all prisoners showing symptoms were tested and where there was evidence of an outbreak, any symptomatic case was assumed to be positive.
Testing was introduced regularly from April 15, when prisons were given sufficient testing supplies.
The data also shows that no inmates died within four weeks of a positive Covid-19 test or clinical assessment determining they had coronavirus.
Alex Hewson, senior policy officer at the Prison Reform Trust, said: “A year on since restrictions were introduced, saving lives has come at a huge price for prisoners and their families.
“Rather than following the advice of their own health experts to reduce prison numbers significantly, ministers chose to enforce a near 24-hour lockdown of people to their six by nine-foot prison cell – often with another person and almost nothing to do.
“Twelve months on that remains the case.
“Releases would have afforded prison staff the vital breathing space to protect lives whilst also protecting efforts for rehabilitation.”
He added that as lockdown restrictions are being eased outside of prison, those in custody are unsure of what the future holds.
“It’s clear that rehabilitation and improving public safety don’t come from locking people up all day, every day,” he said.
“For all the heroic efforts of prison managers and staff, we should remember that their task has been made harder by the overcrowded and dilapidated condition of our prisons before the pandemic began.”
Prison visiting halls closed on March 24 last year before being gradually reopened, and subsequently closed again during 2020.
Currently, all 139 prisons in the UK are only accepting visitors on compassionate grounds.
Prisoners have, in the main part, been kept on 23-hour-a-day cell lockdowns since March 24 last year.
A Prison Service spokesman said: “The tireless work of staff at Lewes, along with measures including routine and mass testing, has saved lives and protected the NHS.”
Secure video call technology has been rolled out in every facility for prisoners to keep in touch with their families, the spokesman said, and specialist officers are giving one-to-one mental health support.
The spokesman said: “Without immediate, decisive action, public health experts warned that thousands of lives could have been lost in prisons.
“We continue to support prisoners’ wellbeing and rehabilitation through vital family contact, education, work and exercise.”