The dose makes the poison. That adage appears true for infections caused by the coronavirus. Scientists state that a few viral particles aren't enough to make you sick. The greater the viral load you sustain, the more likely you can contract COVID-19.

According to The New York Times, researchers working on determining just what the crucial dose could be haven't come up with any answers.

"The truth is, we really just don't know," Angela Rasmussen, a virologist at Columbia University in New York, told the Times. "I don't think we can make anything better than an educated guess."

Based on previous research with other pathogens, Rasmussen said that Sars-CoV-2, the virus that causes COVID-19, most resembles SARS. For SARS, an infective dose is just a few hundred particles, she said.

And there are several other variables to consider. According to the Times, some people are "super-spreaders" and transmit more viruses than others, while on the receiving end, the shape of the nostrils and how much nose hair and mucus are present can influence how much virus enters the body.

Research has shown that the virus thrives in indoor places with poor air circulation. Infectious disease expert Dr. William Schaffner told Business Insider that coronavirus particles more easily linger in the air of enclosed, poorly ventilated spaces. According to Fox News, even loud talking could leave the coronavirus in the air for up to 14 minutes.

"It's clear that one doesn't have to be sick and coughing and sneezing for transmission to occur," Dr. Dan Barouch, a viral immunologist at Beth Israel Deaconess Medical Center, told the Times.

People can also become infected by touching a contaminated surface and then putting their hands to their nose or mouth, although the Centers for Disease Control and Prevention said "this isn't thought to be the main way the virus spreads." Experts believe that inhaling the virus is still the most dangerous mode of transmission.

Larger droplets are heavy and fall to the ground, but tiny droplets that are less than 5 microns in diameter, called aerosols, can linger in the air for hours, increasing the risk of infection, said Barouch.

While researchers are figuring out exactly how the virus is transmitted and how much can make you sick, experts continue to recommend wearing masks in public and avoiding crowded places to reduce the amount of infectious material inhaled.

"This is not a virus for which hand washing seems like it will be enough," Dr. Joshua Rabinowitz, a biologist at Princeton University, told the Times. "We have to limit crowds, we have to wear masks."