The images are compelling: Fire trucks in Tehran or Manila spray the streets. Amazon tests a disinfectant fog inside a warehouse, hoping to calm workers’ fears and get them back on the job. TV commercials show health care workers cleaning chairs where blood donors sat. Families nervously wipe their mail and newly delivered groceries.

These efforts may help people feel like they and their government are combating the coronavirus. But in these still-early days of learning how to tamp down the spread of the virus — whether it’s on steel poles in trains, the streets or the cardboard boxes delivered to homes — experts disagree on how best to banish the infectious germs.

“There is no scientific basis at all for all the spraying and big public works programs,” said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota. “It’s at best wasteful, and at worst we’re just putting disinfectants into the environment that we don’t need.”

Most transmission of the virus comes from breathing in droplets that an infected person has just breathed out — not from touching surfaces where it may be lurking. “Transmission of novel coronavirus to persons from surfaces contaminated with the virus has not been documented,” the Centers for Disease Control and Prevention notes on its website.