When will we have a vaccine? Can you get reinfected? These are the top 10 questions we hope to have answers to in the next 100 days.

Doctors, scientists and epidemiologists have made strides in their research to learn what they can about SARS-CoV-2 and the illness it causes, COVID-19. 

Multiple vaccines are in different stages of development as institutions scrutinize the effectiveness of existing drugs to treat coronavirus patients in clinical trials. Social distancing restrictions and lockdown measures have flattened the curve in parts of the country, and states have begun reopening in phases. 

But experts say that there's more to learn about the virus, and as the United States surpasses 100,000 deaths, many wonder if that learning curve is just too steep. 

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These are the top 10 questions we hope to have answers to in the next 100 days. 

1. When will we have a vaccine?

This is the number one No. 1 question on everybody's mind. Unfortunately, the answer is complicated. 

President Donald Trump announced this month the launch of Operation Warp Speed, a government coordinating effort aimed at securing a coronavirus vaccine by the end of the year.

But vaccine experts have consistently urged caution in presuming a vaccine will be available soon. The White House Coronavirus Task Force's Dr. Anthony Fauci has said that a vaccine is likely within the next year or two, and the process takes time. 

"You can rush vaccine development, but only when you understand – there’s no way around it – you are trading safety for speed," said Dr. Greg Poland, director of the Mayo Clinic's Vaccine Research Group.

Oxford University in England and Maryland-based vaccine company Novavax seem ahead of the global race as their vaccine candidates have shown success in animal trials.

But many experts say the process will be even longer as mass production to make the vaccine widely available to everyone at once is nearly impossible. The government will be forced to decide who will receive the vaccine first and allocate doses accordingly. 

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2. When will there finally be enough testing? 

While testing has accelerated since the Centers for Disease Control and Prevention stumbled in its initial rollout, it's still not perfect. 

Many parts of the country still reserve tests only for patients who present symptoms.

"If you are symptomatic with a respiratory illness, that is an indication for a test and you can get a test. If you need to be contact traced, you can get a test," said Adm. Brett Giroir, the assistant secretary for health at the Department of Health and Human Services.

But studies have shown that many infected people never present symptoms, and public health experts have called for enough testing to reveal the asymptomatic carriers of the disease. 

Trump said 300,000 tests are now being done nationwide every day. But last week, a report from the Harvard Global Health Institute found that the U.S. should be doing 900,000 tests a day by May 15 to safely reopen. 

According to their model, more than 40 states have not reached the level of testing needed, including four – Colorado, Florida, Georgia and Texas – that have already reopened. 

3. When will we know if antibody testing is reliable?

Experts say people should be careful about how they interpret results of COVID-19 antibody tests that haven't been validated by government regulators as manufacturers flooded the U.S. market with tests that vary widely in accuracy. 

The U.S. Food and Drug Administration made the rush to market possible by allowing COVID-19 antibody test manufacturers to self-validate their products without first submitting the data to regulators.

Amid criticism of that policy, the FDA changed course in early May. Citing unnamed “unscrupulous actors” marketing fraudulent tests, the agency said manufacturers must meet new accuracy standards and submit proof of testing quality.

At that point, the FDA had given emergency use approval to 12 out of more than 200 antibody test manufacturers. The FDA is working with other government offices to assess the performance of antibody tests. Results have not been made public.But even if antibody testing gets more accurate with the FDA's new guidelines, experts still can't confirm the presence of antibodies mean immunity to the virus.  

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4. What are possible treatments or prevention methods?

As experts race to find a treatment for COVID-19, the experimental drug remdesivir is showing some promise. Data from a global study released at the end of April found patients given the drug recovered faster and may be less likely to die.

The study, conducted by the U.S. National Institute of Allergy and Infectious Diseases, found patients who received remdesivir had a 31% faster recovery time than those who received a placebo.

Remdesivir is an experimental antiviral drug from the American biotech firm Gilead Sciences. It was originally tested as a treatment for Ebola and other coronaviruses including SARS and is now being tested as a possible COVID-19 treatment.

Many scientists caution, however, against drawing any conclusions about remdesivir and say other recent studies found no clinical benefits to the drug. 

Convalescent plasma and immunomodulators like tocilizumab have been given to patients with COVID-19 in clinical trials, but remdesivir is the only treatment that has been shown to have even a potential effect on the disease. 

Trump confirmed to reporters May 18 that he had been taking the anti-malaria drug hydroxychloroquine daily for the past week and a half; however, there has been no solid evidence of the drug's effectiveness. In fact, doctors caution against using hydroxychloroquine outside of its intended purpose or in clinical trials as the long list of side effects can be harmful. 

5. Can you get reinfected?

Concern for reinfection was initially raised after reports out of South Korea that some people were becoming reinfected with SARS-CoV-2, the virus that causes COVID-19.

The country’s Centers for Disease Control and Prevention reported more than 300 such cases. South Korea has one of the world’s most extensive COVID-19 testing programs, so its data is considered strong. 

South Korean researchers now believe they were seeing false positives, in which the tests detected old particles of virus in patients no longer causing disease, Reuters reported.

It’s still not known whether having had COVID-19 gives long-term immunity to the virus, but immediate reinfection is now less of a worry.

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6. Is it safe to reopen the country?

As states gradually reopen, the question that looms in the coming weeks is whether increased resident mobility leads to a surge in new coronavirus cases.

Texas could be a telling case. The state became one of the first to take aggressive measures, allowing restaurants and retailers to reopen to limited customer capacity May 1. On May 14, Texas reported its highest single-day increase of new cases, with 1,448, according to the Johns Hopkins University data dashboard. 

Fauci, director of the National Institute of Allergy and Infectious Diseases, warned May 12 in a Senate committee hearing that reopening the country amid the coronavirus pandemic may lead to "some suffering and death."

But experts say it's unlikely we'll see a rise in cases in the next few weeks as states reopen for the summer. Officials say we're more likely to see that surge in late summer or fall because the coronavirus incubation spans from about five days to 11 days. 

7. What will America look like after the coronavirus?

Even as states reopen, officials warn residents that life won't be as they knew it. 

Instead, they should expect a "new normal" where sports stadiums remain empty and national parks offer limited services for their visitors.  

The Transportation Security Administration announced changes to its screening process to include social distancing measures, relaxed carry-on liquid requirements and boarding pass etiquette. 

Restaurants were forced to think creatively as they reopened. Some are allowing customers to sit outside on their deck or patio at 50% occupancy. Cities in Florida, Nevada and Maine temporarily closed their streets to allow diners to eat comfortably and safely on the street. 

A restaurant in Ocean City, Maryland, created special tables with oversized inner tubes to keep all clients at least 6 feet apart.

"It's like a bumper boat, but it's actually a table," owner Shawn Harmon said. .

8. What will health care look like?

The health care landscape has drastically changed since the pandemic arrived in the United States.

Doctors restructured office waiting rooms and now greet patients who are daring enough to keep regular visits wearing masks. Hospitals cut elective surgeries, limited visitors and scrambled to provide protection for workers. Tests and annual checkups have been postponed or converted to virtual visits.

Precautions affecting the way most Americans access basic health care are expected to last. Without a vaccine – not expected even optimistically until sometime next year – the risk of transmitting the virus that causes COVID-19 remains high.

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So what will the future of medicine look like as the U.S. adapts to the new pandemic landscape? Expect more remote doctor visits, tenuous hospital care in rural areas and increased preparedness. 

“For years, we’ve talked about the promise of telemedicine and its opportunities,” said Mark Holmes, professor at University of North Carolina Gillings School of Global Public Health. “But what the last two months has shown us is that it could really be a game-changer.”

9. How will the pandemic affect the 2020 election?

Elections are still being held throughout the country even as the threat of infection looms over the heads of voters. 

Wisconsin's Supreme Court overturned the state's stay-at-home orders, and  April's primary resumed; some voters stood in line for hours in the midst of a pandemic. Thousands of absentee ballots either weren’t sent out or ended up lost in the mail, and others were returned too late to be counted. 

Five states allow voters to cast their ballots from home in all of their elections: Colorado, Hawaii, Oregon, Washington and Utah. Those states send registered voters a ballot at least seven days before an election to fill it out at their convenience, and voters either mail it back or drop it off at any center that's closest to them.

While a vote-at-home system may be more efficient overall, the startup costs of implementing it could be substantial. But experts say they may be cheaper over time as the cost of poll workers are much lower. 

And so far, states that use vote-at-home have seen increases in turnout. In a 2019 study of Utah, 21 out of 29 counties conducted general elections by mail. Voter turnout in that 2016 election was 8.7 points higher in the counties that implemented vote-at-home than in those that had not. 

Trump has repeatedly tweeted his opposition to such plans – and just this week threatened to cut off federal funding to two states, Michigan and Nevada – over mail voting. Trump and other Republicans have argued that a vote-at-home system has “tremendous potential for voter fraud.”

But advocacy groups such as the National Vote at Home Institute and the Brennan Center for Justice strongly dispute such claims.

10. How will the pandemic affect the 2020 census?

Before the outbreak, the U.S. Census Bureau had planned to hire as many as 500,000 workers to knock on doors and get households that didn't respond to answer the survey. 

While those hiring efforts are underway online, the agency was forced to suspend field operations in March and only recently restarted those operations in phases. As of May 18, a handful of Area Census Offices made the list.

Agency officials continued to urge people to respond to the Census online, by mail or by phone. Invitations to respond started arriving in households last week.

"We recognize that many people plan to access the 2020 Census through other response modes, such as phone or paper, which is why the 2020 Census has such a nimble design,'' the agency said in a statement. 

Plans for the nationwide count have been underway for years. The population survey is key to apportioning Congressional districts and determining the distribution of billions in federal funds for schools, infrastructure and health systems.

Contributing: Deborah Barfield Berry, Elizabeth Weise, William Cummings, Kevin McCoy, David Heath, Joel Shannon, Lorenzo Reyes and Doyle Rice, USA TODAY; and Patricia McKnight, Milwaukee Journal Sentinel. Follow Adrianna Rodriguez on Twitter: @AdriannaUSAT.