India, April 12 -- China, Australia, Spain among countries with high number of patients with the respiratory infection

Whooping cough, a highly contagious respiratory illness also known as pertussis, is making a concerning comeback across the globe. Outbreaks are being reported in numerous countries, raising concerns about vaccine efficacy and the vulnerability of young children.

China has reported a more than 20-fold increase in whooping cough cases in January and February compared to the same period last year. After confirming 32,380 cases and 13 deaths, Chinese authorities warned that it is a major cause of mortality among infants and young children globally.

However, whooping cough can affect people of all ages when immunity wanes ...