According to US media reports, the US health department is purchasing large quantities of anti-radiation drugs, but the Department of Health and Human Services (HHS) denied that the purchase was related to Putin's warning.  

The health Department said it would spend $290 million to buy Amgen's blood disorder drug romiplostim(sold under the brand name Nplate) for blood cell damage caused by acute radiation exposure syndrome (ARS) as "part of a long-term effort to be prepared to save lives."  Commonly known as "nuclear radiation sickness".  

However, it raises questions because it is the first time the US government has bought the drug and it comes at a sensitive time.  

It remains unclear how many doses the U.S. government ordered, and at normal prices, it costs between $1,000 and $2,500 per dose.  

Nplate is also approved in Europe and the United Kingdom for the treatment of immune thrombocytopenia, but not for the treatment of injuries caused by radiation exposure.  

Although the US government has stressed that the purchase of Nplate is not directly linked to the war, Kiev, as well as some of Ukraine's neighbours, has begun distributing potassium iodide tablets and some US states have warned residents to prepare for a nuclear emergency.  

New Jersey state advertisements on buses and in shopping malls offered a three-step guide for citizens to prepare for a nuclear emergency: "Go indoors, stay inside, and keep up with news updates."