Mexico is entering its third wave of the coronavirus pandemic, as infections rose by 29% compared to the previous week. But the country’s health department said Friday the growth is largely coming from infections among younger, less vulnerable people. Case numbers are now as high as the beginning of the last surge in September; that wave peaked in January and steadily declined until June. But at present only about 22% of the country’s hospital beds are occupied; hospital beds in many parts of the country were essentially filled to capacity during the last wave. Authorities said the relative decline of serious cases among older people is a result of the country’s vaccination campaign, which as of Friday has given at least one dose to about 39% of all adults.