The governor of Georgia said he only recently discovered that coronavirus patients could transmit the virus before they showed any symptoms, as he announced plans for a belated shelter-in-place order across the state.

Governor Brian Kemp had earlier urged Georgia residents to stay in their homes to prevent the spread of the virus, but resisted tougher measures seen in other states until Wednesday, when he made the discovery that had been in the public domain for some months.

"The reason I'm taking this action, like I've continued to tell people, I'm following the data, I'm following the advice of Dr. [Kathleen] Toomey," Mr Kemp said, referring to Georgia’s public health commissioner.

Georgia governor Brian Kemp (Jessica McGowan/Getty Images)

"Finding out that this virus is now transmitting before people see signs, so what we've been telling people from directives from the [Centers for Disease Control and Prevention] for weeks now that if you start feeling bad, stay home... those individuals could've been infecting people before they ever felt bad. But we didn't know that until the last 24 hours,” he said at a press conference. “This is a game-changer for us," he added.

Impact coronavirus is having on Louisiana and New Orleans Show all 25 1 /25 Impact coronavirus is having on Louisiana and New Orleans Impact coronavirus is having on Louisiana and New Orleans A view of empty Bourbon street in the French Quarter amid the coronavirus pandemic in New Orleans, Louisiana Getty Impact coronavirus is having on Louisiana and New Orleans Nyla Clark, 3, accompanied by her mother, Chavonne Clark, sits in a baby stroller at a corner in New Orleans, hoping to get a few dollars from an occasional passerby. Clark was a phlebotomist with a local company until she lost her job because of the coronavirus pandemic. She is waiting for unemployment The Advocate via AP Impact coronavirus is having on Louisiana and New Orleans A man boards a streetcar Reuters Impact coronavirus is having on Louisiana and New Orleans Jackson Square, normally bustling with tourists, is seen deserted AP Impact coronavirus is having on Louisiana and New Orleans Words from Gloria Gaynor's "I Will Survive" are painted onto plywood covering the window of a closed business AFP via Getty Impact coronavirus is having on Louisiana and New Orleans Street performer Eddie Webb looks around the nearly deserted French Quarter looking to make money AP Impact coronavirus is having on Louisiana and New Orleans Boarded up businesses Reuters Impact coronavirus is having on Louisiana and New Orleans The normally bustling tourist mecca of Bourbon Street lies deserted in the early afternoon Reuters Impact coronavirus is having on Louisiana and New Orleans A sign along I-10 informing persons who travel from Louisiana to quarantine AP Impact coronavirus is having on Louisiana and New Orleans A man cycles along Jackson Square AFP via Getty Impact coronavirus is having on Louisiana and New Orleans Elena Likaj, prevention department manager at Odyssey House Louisiana (OHL) which runs a drive-through testing site, takes the temperature of New Orleans resident Peyton Gill Reuters Impact coronavirus is having on Louisiana and New Orleans A man walks his dog past a boarded up business on Frenchmen Street Reuters Impact coronavirus is having on Louisiana and New Orleans An empty Bourbon street Getty Impact coronavirus is having on Louisiana and New Orleans A meal is distributed at the Lantern Light Ministry at the Rebuild Center Reuters Impact coronavirus is having on Louisiana and New Orleans A woman walks in the French Quarter Reuters Impact coronavirus is having on Louisiana and New Orleans People practice social distancing as they queue up for a meal at the Lantern Light Ministry at the Rebuild Center Reuters Impact coronavirus is having on Louisiana and New Orleans French Quarter Getty Impact coronavirus is having on Louisiana and New Orleans A sign is pictured in the French Quarter amid the outbreak Reuters Impact coronavirus is having on Louisiana and New Orleans A view of Bourbon Street Reuters Impact coronavirus is having on Louisiana and New Orleans National Guard members walk down Rampart Street AFP via Getty Impact coronavirus is having on Louisiana and New Orleans A man rides his bicycle in front of a boarded up French Quarter restaurant Reuters Impact coronavirus is having on Louisiana and New Orleans A shuttered business is pictured on Decatur Street AFP via Getty Impact coronavirus is having on Louisiana and New Orleans The normally bustling tourist mecca of Bourbon Street lies deserted Reuters Impact coronavirus is having on Louisiana and New Orleans A view of Canal Street Reuters Impact coronavirus is having on Louisiana and New Orleans A New Orleans firefighter works to contain an early morning fire Reuters

Public health officials have long warned that the virus was spreading between humans before symptoms appeared. On January 31, America's top infectious disease doctor said there was "no doubt" that asymptomatic transmission was occurring after the publication of a study by German researchers. "This study lays the question to rest," said Dr Anthony Fauci, director of the National Institute for Allergy and Infectious Diseases.

A number of scientific studies conducted in the US have since supported that claim. The current guidelines from the Centers for Disease Control and Prevention (CDC) say that “some spread might be possible before people show symptoms, but that “this is not thought to be the main way the virus spreads.”

Georgia currently has 4,638 confirmed cases of Covid-19, with 139 deaths as of Wednesday, Mr Kemp said.

Mr Kemp said his stay-at-home order will go into effect on Thursday and last until April 13. All of the state’s public schools would remain closed for the rest of the year, he added.