Umair Irfan
Former correspondent
Latest articles by Umair Irfan
A mild Covid-19 case from omicron might feel like a cold. You should still take it seriously.
The mutations in omicron hint at what’s to come in the Covid-19 pandemic.
The worst-case scenario with the new variant could be 20 percent more US Covid-19 deaths than last winter.
Omicron may be less risky for each of us — but more risky for all of us.
Vaccinated and confused about whether to get tested? We asked four experts for help.
Surveillance is dangerously inadequate in much of the world.
The biggest climate conference in history was a tiny step toward solving a gargantuan problem.
More money is on the table at the Glasgow climate conference, but it’s not enough.
Why the last week of the COP26 climate change negotiations is so critical.
Half the world has gotten a Covid-19 shot. Yet the vaccination rate in some countries is less than 10 percent.