“There are a couple of studies that show women having more local and systemic reactions to the flu shot than men,” he said. He added the evidence suggests that, overall, women may be “more responsive to vaccinations than men.”

Other clues indicated that man flu is not an overreaction.

“Epidemiologic data from Hong Kong showed that adult men had a higher risk of hospital admission for flu,” Sue said. An American study revealed that men died more often from flu compared with same-age women, regardless of underlying heart disease, cancer, chronic respiratory diseases and kidney diseases.