Emergency supplies of antiviral drugs are being sent to Ukraine, Afghanistan and other countries in Eastern Europe and Central Asia, where hospitals report that they are being overwhelmed by patients with swine flu, the World Health Organization said Thursday.

Ukraine in particular has “a shortage of ventilators and they have counted more than 100 deaths by now,” Dr. Nikki Shindo, a medical officer with the organization’s global influenza program, said at a news briefing.

Alarmed by deaths that health authorities believe could have been prevented with rapid treatment, the agency said it was revising its guidelines and urging more people to take antiviral medication even before they are sure they have the flu.

The new guidelines say that anyone with flu-like symptoms for three days, along with people in several high-risk groups  pregnant women, children under 2 and people with underlying respiratory problems  should not wait for laboratory tests to confirm the diagnosis but should be treated right away with drugs like Tamiflu.