A member of the Mercedes team has tested positive for coronavirus before this weekend's Eifel Grand Prix.
The team said the situation was "being handled in line with FIA protocols, working closely with the FIA".
Hamilton said he was "concerned" and "sad" and emphasised the need to behave appropriately to avoid Covid-19.
"It is important for everyone around the world to be continually reminded this thing has not disappeared. It is still here," he said.
"We still have to follow protocols, wear masks, keep your hands clean and keep your distances.
"I can't say what it will do to our weekend. We have a lot of great people in the team, we will just try to make him proud and it will take a lot of work to make sure we continue on without any disturbances."
Mercedes will make the necessary adjustments to ensure the weekend at Germany's Nurburgring runs smoothly.
Meanwhile Hamilton opposes plans to hold the Brazilian Grand Prix at a new track in Rio De Janeiro to be built on land that is currently forest.
Six-time world champion Hamilton said: "I heard it is potentially going to be a sustainable race.
"But the most sustainable thing you can do is not tear down any trees."
He added: "I don’t think it’s a smart move. There is a global crisis with deforestation."
The Brazilian Grand Prix has been held at Sao Paulo’s Interlagos circuit since 1990 but its contract ended this year. Its race has been cancelled in 2020 as a result of the coronavirus crisis, in which Brazil has been one of the most badly affected countries.