Coronavirus deaths in the United States have surpassed 100,000, more than any other country in the world, according to the New York Times and NBC.
The death toll has led to one somber question: What could the country's leaders have done to prevent this from happening?
While many doctors, scientists and epidemiologists may have their own answers, the truth is that not much was known about COVID-19 when U.S. cases were first recorded in February. The models, studies and data we have now were simply nonexistent three to four months ago, which made it difficult to understand what we were up against.
When combating a new disease, information is everything. Here are 10 facts we wish we would have known 100 days ago.
Timeline:How COVID-19 has unfolded in the US, four months in
1. The virus was spreading faster than we realized
SARS-CoV-2 is an extremely transmissible virus, as models and reports from China have made clear.
Similar to influenza, the coronavirus can be spread from person to person through droplets in the air.
However, one key difference is that COVID-19 can also "spread through the airborne route," according to Johns Hopkins Medicine. This means tiny droplets remaining in the air could infect someone even after the sick person isn't around, its website said.
The coronavirus incubation period, the time between infection and the appearance of symptoms, is also longer. Influenza's incubation period is about three days, while the coronavirus is about five days. More research is needed to confirm if it's possible to shed the virus presymptomatically, but a study form China published in the peer-reviewed journal Nature found that patients were more contagious one or two days before symptoms appeared.
"This damn virus is going to keep going until it infects everybody it possibly can," Dr. Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, said May 11 during a meeting with the USA TODAY Editorial Board. "It surely won’t slow down until it hits 60 to 70%" of the population, the number that would create herd immunity and halt the spread of the virus.
Early studies from China have also indicated the R0 (pronounced R-nought), or the number of people one sick person can infect, was as high as 5.7 in late January. It's important to note that R0 is not a constant number.
The loss is staggering: Honoring the 100,000 lives lost to the coronavirus
2. The virus can live on surfaces for days, but it's not easily spread that way
While respiratory droplets continue to be the virus' preferred method of transmission, researchers discovered that it could also live on surfaces for days introducing another possibility for infection.
A study published in the New England Journal of Medicine in March found that the coronavirus could be detected up to four hours on copper, up to 24 hours on cardboard and up to two to three days on plastic and stainless steel.
The Centers for Disease Control and Prevention has always warned that "it may be possible" to become infected with the coronavirus by touching contaminated surfaces or objects.
It just "does not spread easily" in that manner, the agency now says.
"COVID-19 is a new disease and we are still learning about how it spreads," says the CDC's recently updated guidelines. "It may be possible for COVID-19 to spread in other ways, but these are not thought to be the main ways the virus spreads."
Although the likelihood of infection is minimal, the NEJM study increased hand hygiene awareness and underscored the importance of not touching your eyes, nose and mouth.
3. Pets can test positive, too
As coronavirus cases climbed, another COVID-19-related concern came to light: What about my pets? Although animal transmission is still unclear, officials have reported a few cases.
The most famous case was reported out of the Bronx Zoo. Nadia, a 4-year-old Malayan tiger, was tested after her sister Azul, two Amur tigers and three African lions developed a dry cough. Officials believed the animals became sick after being exposed to a zoo employee who was "actively shedding virus."
A few weeks later, a pug from North Carolina tested positive for COVID-19, possibly the first dog in the United States to be diagnosed with the virus. The family said their pet, Winston, didn't display any severe symptoms, but he was coughing a lot and didn't eat his breakfast one morning.
Both Nadia and Winston have since recovered.
While a study published May 13 found that cats can get infected by the coronavirus and transmit it to other cats, most veterinarians say there isn't too much for owners to worry about when it comes to the family pet and the coronavirus.
Jessica Romine, DVM specialist in small animal internal medicine at Specialty and Emergency Pet Hospital in Southfield, Michigan, said the risk of any pet having a severe case of the coronavirus, the way humans are experiencing, is low.
"There seems to be no evidence that pets can be giving it to people, so they shouldn't be a risk for them licking us or getting it from them," she said. "If anything, it would be the other way around, that a sick person could give it to their own cat or dog potentially."
4. People can shed the virus without any symptoms
Another late discovery was the possibility of transmission via asymptomatic patients, or people who are infected with the virus but don't exhibit any symptoms.
Mass testing at a state prison in Goldsboro, North Carolina, found that more than 90% of the newly diagnosed inmates displayed no symptoms, meaning the deadly virus could have remained hidden had the state followed federal guidelines that largely reserve testing for people displaying common symptoms.
“We would never have known,” North Carolina Department of Public Safety spokesman John Bull said.
According to officials at Marion Correctional Institution in Ohio, 152 prisoners were tested in one dormitory and 39% tested positive for COVID-19 even though they displayed no symptoms.
Experts quickly realized scanning, testing and public regulations needed to be changed to accommodate the possibility that people can transmit the virus without having any common symptoms.
5. Wearing masks: CDC said no, then yes
This led to changing mask recommendations.
For months, the Centers for Disease Control and Prevention urged the mass public not to wear a mask unless they were sick or caring for a COVID-19 patient, citing concerns about supply and effectiveness.
They reversed that guidance in early April. Now, the CDC recommends people wear homemade or cloth masks in public.
"With increasing evidence for asymptomatic and presymptomatic transmission of COVID-19, the argument for wearing a face covering is becoming more compelling," said Dr. Robert Glatter, emergency physician at Lenox Hill Hospital in New York City.
Officials recommend wearing masks in public settings where social distancing measures are difficult to maintain, such as grocery stores and pharmacies. Many cities and states require masks in public, including New York, New Jersey and Los Angeles.
6. Testing was not widely available
Testing has always been an important component to containing a disease, but many critics say the U.S. government failed to urgently roll out tests and make them widely available.
The nation’s testing problems have been well-chronicled.
Flawed test kits were shipped in February to state and county public health labs nationwide. The nation’s vast network of hospital and private commercial labs did not get the Food and Drug Administration’s regulatory green light until the end of February.
The trickle of tests could not match the speed of the virus, which gained a foothold in metro Seattle in January and later New York City. Cases proliferated in Chicago, Miami, New Orleans and several other cities as public and private labs worked round the clock to catch up and faced limits on testing supplies.
Although testing has accelerated since, many experts say it's not enough to get an accurate picture of U.S. cases because testing is still restricted in parts of the country and a backlog of tests have produced delayed results.
7. Additional symptoms of COVID-19
When the World Health Organization and the CDC first warned about the new coronavirus, they urged the public to be on the lookout for these three main symptoms: fever, dry cough and difficulty breathing.
Since then, doctors have been able to identify more symptoms in patients.
There are now six new symptoms that the CDC cautions could be signs of the coronavirus: chills, repeated shaking with chills, muscle pain, headache, sore throat and a loss of taste or smell.
Experts say the sudden loss of smell can be attributed to damage or inflammation to nerves in the nasal cavity.
“The same way we have nerve endings that stimulate someone to cough, we have those nerve endings in our nose that are responsible for our sense of smell,” said Dr. Raphael Viscidi, an infectious disease specialist at Johns Hopkins Medicine. “It could be a sign that the nerve endings are inflamed.”
Coronavirus symptoms:How does the coronavirus cause COVID toes or loss of smell? Here's how the immune system reacts
Another perplexing reaction associated with the coronavirus is known as “COVID toes.” The American Academy of Dermatology (AAD) has compiled a registry of skin manifestations associated with COVID-19. About half of the more than 600 cases on the registry are COVID toes.
Dr. Esther Freeman, director of Massachusetts General Hospital Global Health Dermatology and member of the AAD task force on COVID-19, said COVID toes are pinkish-reddish “pernio-like lesions” that can turn blueish-purple over time.
8. The coronavirus can induce blood clots
Reports from China prepared U.S. doctors for a respiratory disease that primarily attacked the upper and lower respiratory tract, primarily in the lungs.
But then over a two-week period, Mount Sinai doctors reported five patients under 50 who suffered large-vessel strokes, according to a letter they published in the New England Journal of Medicine.
All five patients tested positive for COVID-19 but had mild to no symptoms.
“That creates a big alarm,” said Dr. J Mocco, director of the Cerebrovascular Center at Mount Sinai and one of the letter’s authors. “Our spider sense goes up to say that there’s something not right here.”
Mocco said he has heard from colleagues in heart, lungs and kidney medicine who have also seen complications in coronavirus patients caused by blood clots.
Virus that leaks into the blood binds to endothelial cells located in the inside lining of the blood vessel. Both endothelial cells in the blood vessel and epithelial cells in the respiratory tract have the same protein receptor that binds with the virus.
Once the virus attaches to the protein receptor on the outside of the endothelial cell, the virus penetrates it and multiplies inside. Damage to these cells triggers a response that promotes blood clotting.
If clots form in larger blood vessels and increase in size over time, they can be dislodged and travel to other places in the body, said said Dr. Raphael Viscidi. Clots in the veins go to the lungs and can cause a pulmonary embolism, while clots in arteries can go to the brain and cause a stroke.
9. Children are not immune to complications from the virus
Even though younger people are still less likely to develop severe complications from COVID-19, pediatricians are alarmed at an unfamiliar disease targeting children and adolescents.
Doctors are calling the new ailment pediatric multisystem inflammatory syndrome, and it shares some traits with Kawasaki disease, which typically afflicts children under 5 years old. The common symptoms: prolonged fever, a rash, conjunctivitis, swelling of the palms or soles of the feet, sometimes peeling of the skin in those areas and lymph node enlargement.
Dr. Sunil Sood, a pediatric infectious disease physician at Northwell Health's Southside Hospital and Cohen Children's Medical Center, says patients he has treated have been sicker, with inflammatory markers 10 to 100 times higher than the average child with Kawasaki disease.
Multi-system inflammatory disorder:More kids fall ill to mysterious Kawasaki-like disease as officials test for coronavirus
He estimates his patients may have had the virus, even unknowingly, four weeks before developing the inflammatory condition.
"The immune system can overreact in a delayed timeline many weeks later," Sood said. "We know this from other infectious diseases."
The disease causes low blood pressure and a rapid heartbeat in children, with some patients developing inflammation of the heart as well as liver and kidney failure. Older children also have been affected.
Sood advises parents and pediatricians to look out for a fever as well as a combination of any of these symptoms: abdominal pain, confusion, diarrhea, red eyes, rash, swollen hands and feet, difficulty breathing and passing out. Sometimes the abdominal pain can be so severe it mimics appendicitis.
10. Early lockdowns could have saved lives
The U.S. had responded later to the pandemic than the rest of the world, implementing lockdown and social distancing restrictions in mid-March.
A study from Columbia University published in MedRxiv shows this delayed response may have cost thousands of lives in a matter of weeks. According to the report, if the country had adopted lockdown measures one week earlier, it would have avoided 703,975 confirmed cases and 35,927 deaths as of May 3.
The numbers are more harrowing if the lockdown measures were adopted two weeks earlier. Columbia researchers reported the U.S. could have prevented 960,937 confirmed cases and 53,990 deaths. In New York City alone, a difference of two weeks would have meant 20,427 lives saved.
While modeling is never perfect, the study's authors note most of the data came from metropolitan areas and the experiments are based on "idealized hypothetical assumptions."
Contributing: Ken Alltucker, Jorge Ortiz, Joshua Bote, Ryan Miller and N'Dea Yancey-Bragg, USA TODAY; Meredith Spelbring, Detroit Free Press; and The Associated Press. Follow Adrianna Rodriguez on Twitter: @AdriannaUSAT.