Clive Wright, the region's Covid regional convenor, said there was concern over the slow decline in infections, which remain second highest in the country behind London.
He said NHS chiefs believed this was down to the new variant of coronavirus hitting the West Midlands later than other areas, meaning case rates were likely to stay high for the foreseeable future.
He warned that the virus was mainly being transmitted by people catching it at work and then infecting people at home.
It came as Boris Johnson warned that evidence suggested the new variant could be more deadly.
The UK's R number – which measures whether the epidemic is growing or shrinking – is at or below one for the first time since early December, but in the Midlands it is estimated to be between 0.9 and 1.2.
The region also has some of the highest infection rates in the country, with Sandwell - on 920.4 cases per 100,000 in the seven days to January 17 - and Wolverhampton (876.4) both in the top five.
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Speaking at the region's weekly Covid briefing, Mr Wright, said: "We are concerned that rates are not falling as quickly as some other regions.
"The West Midlands region currently has the second highest of all age case rates nationally, only superseded by London.
"Our case rates in the over-60 age group are also not reducing as we would hope, and this will continue to put pressure in our NHS systems.
"We believe that the comparatively slower decrease is due to the new variant of the virus, which reached the West Midlands later than other parts of the country and is now playing out here.
"The positive impact of lockdown means our peak of cases is lower than it could have been, but the tail off will be longer."
Mr Wright also called for people to make sure they stick to Covid guidelines at work.
"The new variant of the virus is much more contagious and spreads quickly," he said.
"We know that transmission is mainly in households; the working age population are catching the disease mainly at work then bringing it back to the home."
He said it was vital that employers operate Covid-safe practices, and that workers don't car share and maintain social distancing during breaks.
People should get a test at the first sign of symptoms, he added, saying: "It is crucial now that none of us let our guard down at any time."
Mr Wright said the lockdown was likely to last for some time after Ministers reviewed the national measures this week.
"We need to get the virus down to a much lower level and to take the pressure off the NHS before we exit from any lockdown," he said.
The Black Country recorded 8,099 new cases in the seven days up to January 17, with Walsall's infection rate standing at 745.8 cases per 100,000 people, and Dudley's at 668.9.
South Staffordshire's rate is 608.3, while in Cannock Chase it is 519, Lichfield's is 389.5, and the rate in Stafford is 378.1.