The C.D.C. changes testing guidelines to exclude those exposed to virus who don’t exhibit symptoms.

The Centers for Disease Control and Prevention quietly modified its coronavirus testing guidelines this week to exclude people who do not have symptoms of Covid-19 — even if they have been recently exposed to the virus.

Experts questioned the revision, pointing to the importance of identifying infections in the brief window immediately before the onset of symptoms, when many individuals are thought to be most contagious.

COVID-19: How South Korea Prevailed While the U.S. Failed In a commentary in "The American Journal of Medicine," researchers demonstrate the stark differences in public health strategies from two democratic republics: South Korea and the United States. FloridaAtlantic

COVID-19 is now the third leading cause of death in the United States. The U.S. accounts for about 25 percent of COVID-19 cases (4.4 million) and deaths (170,000) in the world today while comprising less than 5 percent of the population.

Facing 2nd virus wave, Spain tracks infections with soldiers MADRID (AP) — Under strain from Europe's fastest-growing wave of coronavirus infections, the Spanish government cleared the way for more localized lockdowns Tuesday and deployed the military to... AP NEWS

MADRID (AP) — Under strain from Europe’s fastest-growing wave of coronavirus infections, the Spanish government cleared the way for more localized lockdowns Tuesday and deployed the military to bolster the country’s faltering attempts to trace infections.

Protecting COVID-19 vaccine research from cyber espionage What will soon be the most valuable asset in the world? A vaccine for COVID-19. What are we doing to protect it from cyber espionage? In Homeland Security Staff In Homeland Security

The glory of the prize—in lives saved, reputations made, and profits earned—is incalculable. The hunt for a cure has unleashed an epic arms’ race among world powers, multinational corporations, and universities. And as with any arms’ race, not everyone is playing by the rules.

Africa declared free of polio Nigeria is now rid of wild polio having had more than half of global cases less than 10 years ago. BBC News

Africa has been declared free from wild polio by the independent body, the Africa Regional Certification Commission.

Polio usually affects children under five, sometimes leading to irreversible paralysis. Death can occur when breathing muscles are affected.

Twenty-five years ago thousands of children in Africa were paralysed by the virus.

The disease is now only found in Afghanistan and Pakistan.

There is no cure but the polio vaccine protects children for life.

FDA chief apologizes for overstating plasma effect on virus WASHINGTON (AP) — Responding to an outcry from medical experts, Food and Drug Administration Commissioner Stephen Hahn on Tuesday apologized for overstating the life-saving benefits of treating... AP NEWS

WASHINGTON (AP) — Responding to an outcry from medical experts, Food and Drug Administration Commissioner Stephen Hahn on Tuesday apologized for overstating the life-saving benefits of treating COVID-19 patients with convalescent plasma.