On September 18 Orianna Carvalho woke up at three A.M. with a sore throat and the sniffles. At first, she idea her symptoms were acquired by allergies. Simply as the minutes ticked by, she began to worry they were caused by COVID-19. The post-obit morning time, Carvalho got tested at the University of Rhode Isle, where she is a first-twelvemonth doctoral student. Over the next few hours she developed a fever, and the catastrophizing began in hostage. When Carvalho finally learned that the cause of her misery was not COVID merely the common cold, she was relieved only also surprised. "I have been so conscientious—wearing a mask every fourth dimension I go somewhere, keeping at to the lowest degree six feet away from other people, using paw sanitizer and washing my hands," she says. "I don't know how I got sick."

Carvalho is not alone. Many Americans have been puzzled to find that their best efforts to avoid COVID-19 have not always protected them from less troubling infections such every bit colds, breadbasket bugs and strep throat. How have other pathogens slipped through our anti-COVID defenses? There are no clear-cut answers, merely the work of infectious disease specialists, virologists and epidemiologists—much of information technology conducted decades before the electric current pandemic—provides some clues. Their enquiry shows that many microbes are more numerous, hardy and contagious than SARS-CoV-2, the virus that causes COVID-19. And for many of u.s.a., even our best efforts are not good enough.

The public health measures taken to stem the spread of SARS-CoV-2, which has been responsible for the deaths of more than 207,000 people in the U.S. to date, have also afflicted the prevalence of other respiratory viruses. This year the Southern Hemisphere essentially skipped flu flavour, which typically hits countries such as Australia, Republic of chile and S Africa in May or June. Information from Commonwealth of australia advise that although pandemic restrictions pushed many not-flu viruses out of circulation, a group of cold-causing pathogens known as rhinoviruses stuck around. A similar trend could exist in store for the U.S., co-ordinate to researchers who are tracking transmission of respiratory viruses in New York State, Washington State and Texas. Pedro Piedra, a pediatric infectious disease specialist at Baylor College of Medicine, says that although he has seen a significant decrease in many common respiratory viruses during the pandemic, he has noticed an uptick in rhinoviruses this fall.

Some virologists believe that the sheer number of viruses that cause the common cold can make information technology exceedingly difficult to avoid communicable i: at that place are around 200 different pathogens. These include four coronaviruses (the grouping that includes SARS-CoV-2); 4 parainfluenza viruses (which, despite their name, bear no relation to influenza viruses); respiratory syncytial virus; and 160 different rhinoviruses. Viral censuses have revealed that dozens of these rhinoviruses circulate in whatsoever one identify at a given time. "You might be allowed to the flu, just you are not going to be immune to all those rhinoviruses," says James Gern, a rhinovirus researcher at the University of Wisconsin–Madison. "That's one unique feature of rhinoviruses—yous are always going to exist susceptible to some."

But there is only 1 SARS-CoV-two virus, and it has proved to be more enough to wreak havoc on our lives. The persistence of rhinoviruses during the pandemic may exist the event of not only their impressive number merely also their primitive nature, says Ian Mackay, a virologist at the Academy of Queensland in Commonwealth of australia. Similar to the flu virus, SARS-CoV-2 is a more highly evolved virus that is enclosed in a fatty "lipid" membrane. This envelope can cloak the pathogen from antibodies deployed past the human immune system, enabling it to infect cells undetected. But it can also break downwardly after exposure to the environment or a good handwashing, rendering the virus harmless. Rhinoviruses, on the other hand, never evolved an envelope. These so-called naked viruses, which also include the gut-distress-inducing noroviruses, are more resistant to sanitizers and disinfectants and may last longer on fingertips and surfaces.

Although information technology is possible to pick upwards respiratory viruses from contaminated surfaces, well-nigh experts say we are more likely to go ill through contact with infected people. In 1969 half of a grouping of men wintering at a remote Antarctic base adult signs and symptoms of the common cold later being isolated for 17 weeks. Scientists never identified the source of the outbreak, but Mackay and others think it is possible that the men entering the base might not have been every bit healthy every bit they looked. Asymptomatic spread has gotten a lot of attending during the COVID-19 pandemic: studies suggest 40 to 45 percentage of SARS-CoV-ii transmission comes from people not yet showing symptoms. Many colds and flus may also be passed along by people who do not take symptoms, although to what extent this spread occurs is an open up question. At to the lowest degree one written report detected rhinoviruses in a 3rd of asymptomatic children.

"Children, in particular, are a petri dish for manual," says >Arnold Monto, an epidemiologist at the University of Michigan, who studies the spread of respiratory illnesses within households. Because kids are prone to eye rubbing and olfactory organ picking, they can quickly contaminate their habitation with a menagerie of viruses and leaner. Unlike the astute respiratory infections that typically come and go in a matter of weeks, children can harbor chronic infections with leaner—such as Streptococcus pyogenes, which causes strep throat—for months before e'er making themselves or others sick. Tara Smith, an epidemiologist at Kent State University, says it is unclear how such leaner move from harmless colonizer to invasive pathogen, but the stress of the pandemic could play a role. And kids are not the only germ factories in our homes: pets are common carriers of many pathogens. "People probably get ill from their animals more than than we realize," Smith says.

Despite the myriad possibilities, many experts believe the caption for why some of united states of america are still getting routine infections is adequately mundane. "Some people may think they are ameliorate protected than they really are," Smith says. Gern agrees: "If cold viruses are withal spreading, that means nosotros are still having person-to-person contact," he says. We live in a world where one time beneficial deportment—such every bit hugging a friend or going to the gym—now pose heightened risks to our health. For her part, Carvalho thought she was doing everything she could to be prophylactic. After months of staying home, she returned to the gym for some socially distanced martial arts. She now suspects that it is how she got sick.

Since the commencement of the pandemic, more than 80,000 people who wondered if they had a COVID infection have called the telemedicine company Physician on Demand, according to Prentiss Taylor, a physician and the visitor's vice president of medical affairs. More than than half of those cases were not referred for COVID-19 testing considering some other respiratory illness was accounted more likely. Under the circumstances, communicable a common cold instead of COVID might experience similar dodging a bullet. But the fact that other viruses have been able to slip through our defenses could serve every bit a warning for future pandemics, Mackay says. "If we e'er encounter a new rhinovirus come forth, nosotros volition have even more trouble containing it than SARS-CoV-2. A rhinovirus pandemic would be a massive threat that would spread similar that," he adds, snapping his fingers. "And there's no guarantee it would only crusade common colds."