The latest outbreak has infected nearly a sixth of the state legislature, including the leaders of both chambers, following an active legislative period at the capital – including measures to remove the Confederate battle flag from the state's flag – at which many members failed to wear any face coverings.
Mississippi's surging Covid-19 cases follow a worrying trend across the south and in several other states, including California, as new confirmed infections in the US swelled by 1 million within the last month alone.
More than 50,000 coronavirus patients across the US are hospitalised, including 7,000 people in Florida, which eclipsed 11,000 new cases on Friday, the second time within a week that the state has seen more than 11,000 cases in a single day.
Mississippi Governor Tate Reeves, who has tested negative for the virus, said he has had "limited contact with the people who were diagnosed" though the state's Lt Gov Delbert Hosemann and House Speaker Philip Gunn stood beside him during a recent signing ceremony at the governor's mansion. Both men have tested positive for the virus. Neither wore a mask.
All state officials have been urged to get tested, as the state's health officer Thomas Dobbs warns that the number of infected Mississippi officials will "almost certainly" increase in the coming days, he said on Wednesday.
Mississippi Rep Ronnie Crudup Jr, who has also tested positive for coronavirus but has not presented any symptoms, said he wore his mask "95 per cent of the time" when he was at the capital and in public places "but that 5 per cent can make a big difference".
On Thursday, the governor mandated face coverings in 13 counties where Covid-19 has spiked.
The legislature was last in session on 1 July, though lawmakers have not yet passed a budget for the following fiscal year. But Mr Reeves said on Wednesday that the risk of exposing lawmakers in "that fishbowl of the Mississippi Capitol" would be too great.
At least five of the state's largest hospitals have reported running out of intensive care unit beds as the state's new infections climb past 1,000 over a seven-day average. Deaths among people who were not living in long-term care facilities also have spiked.
States across the south are shredding single-day case records.
Louisiana saw its second-highest daily case count on Friday, when new infections topped more than 2,600. The state's health department also recorded 25 deaths, the highest increase in more than two weeks.
"The deaths that we're seeing announced today and yesterday – which are now over 100 – those are people who likely contracted COVID-19 in late May," he told a local television news outlet. "The worst is yet to come as we work our way through that massive increase in people testing positive."
Nearly 30 per cent of coronavirus tests in Miami-Dade County – one of the largest metro areas in the US – are coming back positive. Hospitalisations in Miami have increased by more than 76 per cent within the last two weeks.
Alabama hospitals, strained by an influx of coronavirus patients this week, hit a sixth straight day of record-breaking numbers of hospitalised patients on Friday.
More than 1,100 people in the state are hospitalised, accounting for a third of all hospitalisations since the beginning of the public health crisis.