Dr Justin Varney warned that should virus cases in Birmingham rise to levels experienced in Manchester, 50 other local authority areas would be affected and "the country will go soon afterwards".
Birmingham's director of public health said the trend of rising cases of the Delta variant across the West Midlands was already leading to increased hospital admissions, which he expected to eventually progress to a spike in deaths.
He said this meant it was crucial that the vaccine rollout was ramped up further to ensure it reached as many people as possible.
The infection rate in Birmingham is 131.9 cases per 100,00 people after cases surged by more than 40 per cent in a week to 1,506, while in Manchester it is up to 377.5 cases per 100,000 people.
Dr Varney, who is said areas including Sandwell were experiencing an increase in infection rates due to the number of people travelling across the region as businesses have re-opened.
He warned: "If Birmingham tips to the point of Manchester with 300-plus cases, it’s estimated that Birmingham will take 50 local authority areas and the country will go soon afterwards.
"This is the reason we have had extra vaccine supply and increased testing.
"This is now translating into hospitalisation, moving into double figures and resulting in more people in intensive care beds.
"The trend it goes in will progress to deaths, and we are in the timeline I would expect for it to go that way."
Dr Varney was speaking at the Greater Birmingham Chambers of Commerce's 'road to recovery' online event.
He urged businesses to help curb the spread of the virus by making vaccines as accessible as possible in order to avoid workplace outbreaks.
He said: "Employers need to give their staff time to get vaccinated, changing HR policy if needed. Particularly with large employers of 100 staff or more, there is always the potential to do a vaccine bus visit to work sites.
“Every adult should be testing twice a week with lateral flow, even if they’ve been vaccinated. This is because we need to be aware if the new variant can override the vaccine.
“Essentially vaccination rates need to be much higher, especially in younger groups as that’s where outbreaks are surging.”