He was taken to a hospital near Peshawar, according to the Associated Press news agency, for treatment for minor injuries.
Intelligence officials said that security guards attempted to block the suicide bomber from reaching Mr Sherpao.
A number of people are also reported to have been injured in the blast, including Mr Sherpao's son.
Pakistan's president, General Pervez Musharraf, is a key ally to the US in its war on terror, including cooperation in matters related to the troublesome Afghan border and terrorist activity in the region.
General Musharraf escaped injury after two bombings in 2003 which killed 17 people.
The Foreign Office has said there is a high risk of terrorism and sectarian violence within Pakistan and attacks can occur indiscriminately in public places.
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