5G会导致或传播新冠病毒吗？听听专家怎么说

Online conspiracy theories linking 5G wireless service to the novel coronavirus outbreak had some dangerous real-world consequences last week, despite scientists saying there is no connection between the technology and the spread of the disease. Arsonists in the U.K. set on fire 5G wireless towers in Birmingham, Liverpool, and Merseyside and then uploaded videos of the vandalism to social media.

There's no connection between 5G, the new, superfast successor to 4G wireless, and the deadly pandemic sweeping the globe, scientists say. But the vandalism and false connections between the disease and 5G come as a larger and more rational debate continues over the broader impact of wireless phone gear on human health.

Mobile phones and cell towers transmit radio signals at frequencies well below those of X-rays and ultraviolet light, which are strong enough to damage human cells and DNA and are categorized as ionizing radiation. The lower bands, encompassing everything from AM radio to cell phones to microwave ovens, are categorized as nonionizing radiation and don't harm DNA directly. They have long been considered harmless except for potentially heating cells at close range.

That was before billions of people started relying on nearly constant mobile connections via cell phones. So far, scientific studies of cell phones have offered a mostly reassuring view of the situation. And leading national authorities like the Food and Drug Administration, the National Cancer Institute, and the Federal Communications Commission maintain that there is little to no health risk from using mobile phones given the safety limits already in place.

Still, that has not stopped cities and countries worldwide from slowing or even banning the installation of 5G gear due to health concerns. And some Wall Street analysts say such fears could have a material impact on companies counting on 5G to bolster their sales.

Here are answers to some of the top questions people have about wireless technology and safety:

Did 5G cause or help spread the coronavirus?

The answer to 5G involvement with the coronavirus is simple and straightforward, according to every scientist and doctor that Fortune spoke with. There simply is no connection between 5G and the novel coronavirus known as COVID-19. There is no mechanism by which a wireless technology could cause a virus to mutate into a killer epidemic and no way that wireless airwaves can transmit viruses. It is, as Stephen Powis, medical director for the British National Health Service, says, "complete and utter rubbish."

Some claimed that 5G wireless may have made people more susceptible to the coronavirus by weakening their immune systems. That theory is "based on nothing," says Eric van Rongen, a biologist who has been studying the health effects of electromagnetic fields for decades and currently chairs the International Commission on Non-Ionizing Radiation Protection, a nonprofit formed in the 1990s to offer scientific advice on the issue to policymakers.

"There are no indications from scientific studies that 5G, or any other G, affects the immune system," he says. "If that would be the case, we would have seen effects on the scale and severity of infectious diseases already decades ago. And we don’t."

Wireless technology in general is beneficial as societies go on lockdown to combat the virus, adds Leeka Kheifets, an epidemiology professor at the University of California at Los Angeles who has studied cell phone health effects. Wireless gadgets "make social distancing more possible, by allowing more people to work from home, and more bearable, by allowing people to stay connected with friends and family," she says.

Do cell phones cause cancer?

Almost nine years ago, the World Health Organization classified the emission of the radio frequencies used in cell phones as "possibly carcinogenic to humans." The edict from 2011 was based on early studies that some wireless phone users were getting a type of brain cancer known as glioma at a higher rate than normal. More than 300 substances share the same WHO categorization of "possibly carcinogenic," including aloe vera extract, traditional Asian pickled vegetables, and exposure to dry-cleaning fumes.

However, subsequent research has not proved the link or prompted the WHO to upgrade cell phones to a riskier category.

In a review of all studies done from 2008 to 2018 published by the Food and Drug Administration in February, the agency concluded that there was "no consistent or credible scientific evidence of health problems caused by the exposure to radio frequency energy emitted by cell phones." Similarly, the Federal Communications Commission says that the "available scientific evidence to date does not support adverse health effects in humans." And the National Cancer Institute, which has a lengthy web page about cell phone health research, notes: "The most consistent health risk associated with cell phone use is distracted driving and vehicle accidents."

Another way to consider the risk is to look at the rates of brain cancer and other illnesses in the general population that may be affected by cell phone use. Large studies of cancer trends have found no uptick that would correspond with the massive increase in mobile phone usage. The observed incidence of glioma, for example, "remains relatively stable," says Quinn Ostrom, a career cancer epidemiologist who works at the Baylor College of Medicine in Houston. "We would expect to see an increase in incidence of these tumors if there was an increase in risk for brain tumor with exposure to cellular phones," she says.

Aren’t there some studies that link cell phone radiation and cancer?

Among the studies included in the previously mentioned reviews by medical experts and agencies are some with troubling findings. But they all have limitations and, in some cases, serious flaws.

One of the most careful studies that found possible risks was by the National Toxicology Program, a unit of the National Institutes of Health, that concluded in 2018. The study subjected rats and mice to cell phone signals for up to nine hours daily for several years. Although the findings for mice and female rats raised no alarms, the study found elevated rates of brain and heart tumors in male rats. More troubling was that the types of tumors the rats developed were similar to those found in earlier Scandinavian studies of human cancers and cell phone use.

"The original question that we set out to study was whether it was biologically possible that this could happen, and we found it is feasible that animals could get these tumors," says John Bucher, a senior scientist at the NTP who worked on the study. "But our studies were done under extraordinary conditions."

The rats got large and steady doses for nine out of every 18 hours a day. "I would say it's not directly applicable to how humans use cell phones, but it raises questions that we have to pay attention to," he says. NTP is continuing to study the issue with even more carefully designed studies.

Although the NTP study is somewhat concerning, the overall benefits of using wireless technology still outweigh the risks, says UCLA epidemiologist Kheifets. Still, she agrees with Bucher that "much more research on changes in exposure and potential health effects, not just cancer, is needed."

Does 5G pose unique risks?

Some of the airwave bands used in 5G are different from the bands used in 4G and earlier mobile networks. The new 5G spectrum, known as the millimeter wave band, doesn't travel as far as the bands used for 4G, which has prompted the wireless industry to deploy tens of thousands of smaller cell sites scattered throughout major urban areas.

Studies of this type of radiation don't indicate any unique dangers, however. The International Commission on Non-Ionizing Radiation Protection, which suggests safety limits for phones, recently issued new recommendations for 5G that were mostly similar to its cell phone guidance from 1998. Chair Eric van Rongen says the group reviewed years of research on all possible adverse health effects.

"An overwhelming amount of scientific research suggests that 5G signals will not cause harm, as long as the safety limits are observed," adds Faraz Hasan, a researcher at Massey University in New Zealand who has studied the health effects of 5G technology specifically.

How can I use a cell phone safely?

Given even the small degree of risk found in some studies, concerned cell phone users can follow a few precautions to minimize their exposure. The effect of cell phone signals falls off quickly with even a little distance, Bucher notes.

"The simple way of minimizing exposure is by not holding a phone near your body, to your head or in your pocket," he says, advising users to hold a phone slightly away from their ear when listening to a call, using headphones, and not carrying devices in pants pockets. "Keep some distance, even a few inches, between yourself and the phone," he says.