Past Covid-19 Infection Gives Vaccine-Like Immunity For Months, Study Finds

Coronavirus immunity: What do we know? | COVID-19 Special - YouTube

TOPLINE

Most people who have recovered from Covid-19 have similar levels of immunity against future infection to those who received a coronavirus vaccine, a study by Public Health England found, offering early hope against fears of a short-lived immunity spurred on by reports of people catching the virus twice, though the researchers warn that those with immunity may still be able to carry and transmit the virus to others. 

KEY FACTS

Naturally acquired immunity from a previous Covid-19 infection provides 83% protection against reinfection when compared with people who have not had the disease before, government researchers found in a study of more than 20,000 healthcare workers.

The study, which has not yet been peer reviewed for rigor by other scientists, shows that this protection lasts for at least five months and is at a level just below that offered by vaccines from Pfizer-BioNTech (95%) and Moderna (94%) and significantly above that of the vaccine developed by the University of Oxford and AstraZeneca (62%), though manufacturers don’t know for how long this immunity lasts.

The figures suggest reinfection is relatively rare — occurring in fewer than 1% of the the 6,614 people who had already tested positive for the disease — though the scientists warned that while “those with antibodies have some protection from becoming ill with Covid-19 themselves,” early evidence suggests that they can carry and transmit the virus to others.

“It is therefore crucial that everyone continues to follow the rules and stays at home, even if they have previously had Covid-19, to prevent spreading the virus to others,” Public Health England wrote.

The study will continue to follow participants for another 12 months to determine “how long any immunity may last, the effectiveness of vaccines and to what extent people with immunity are able to carry and transmit the virus,” as well as investigate the highly-contagious new variant of coronavirus spreading across the U.K.. 

CRUCIAL QUOTE

Professor Lawrence Young, a virologist and Professor of Molecular Oncology at Warwick Medical School in England, said an important takeaway from the study is that we don’t yet know how long antibody protection will last outside of the five month window. He said it is “possible that many people who were infected during the first wave of the pandemic may now be susceptible to re-infection.” Young said it will be interesting to see whether people previously infected with Covid-19 and are subsequently vaccinated have “an even longer-lived protective immune response” and whether or not these findings hold true for the new virus variant currently spreading in the U.K..

WHAT TO WATCH FOR

The information gathered from reinfection cases could prove important as the pandemic progresses, especially when it comes to designing and implementing an effective vaccination program and deciding whether to ease lockdown measures. Whether or not those who are immune to serious illness are capable of transmitting the infection to others will be a crucial deciding factor.

WHAT WE DON’T KNOW

It’s not yet clear for how long the protection provided by vaccines last. This will have to be studied over time, as with this case of natural immunity, and is something manufacturers are already doing. Moderna believes their vaccine offers at least a year’s protection against disease. Whether or not this protection prevents individuals from infecting others will also need to be figured out. 

BIG NUMBER

384,784. That’s how many people have died from Covid-19 in the U.S. since the pandemic began, according to Johns Hopkins university. According to CDC projections, this figure is set to grow 25% in the next three weeks. At the moment, more than 23 million people have contracted the disease in the U.S..

More than 10 percent of the U.S. Congress has tested positive

Which Members of Congress Have Tested Positive for the Coronavirus - The  New York Times

At least 60 sitting members of Congress — more than one in 10 — have tested positive for the coronavirus or are believed to have had Covid-19 at some point since the pandemic began. The list includes 44 Republicans and 16 Democrats.

That’s a higher proportion than the general population. As of Wednesday, a bit fewer than one in 14 Americans are known to have had the virus, according to a New York Times database, though many more cases have probably gone undetected.

Five House members have reported positive tests since the attack on the Capitol last week, when many lawmakers were holed up in a secure location together and some refused to wear masks — a situation that angered several Democrats, including Representative Pramila Jayapal of Washington, one of those who has since tested positive. Congress’s attending physician warned members afterward that it was possible they were exposed while sheltering and recommended that they get tested.

Congress has struggled to stem the spread within its ranks in recent weeks. Most members who have tested positive have done so since the election in November, as coronavirus cases have surged across the country.

Representative Jake LaTurner, Republican of Kansas, said he received word just after the attack on the Capitol last Wednesday that he had tested positive, and did not return to the House floor for a vote early on Thursday.

Representative Gus Bilirakis of Florida and Representative Michelle Steel of California, both Republicans, were absent from the House floor when the mob entered the Capitol because each had received positive test results earlier that morning. Representative Chuck Fleischmann, Republican of Tennessee, said on Sunday that he had tested positive after exposure to Mr. Bilirakis, with whom he shares a residence.

Covid-19 Live Updates: Distracted by D.C. Political Crisis, U.S. Sets Daily Record for Virus Deaths

Moving a Covid-19 victim from a hospital morgue in Baltimore last month.

More than 4,400 people in the country died of the coronavirus on Tuesday, the day before lawmakers were set to charge President Trump with inciting last week’s violence at the Capitol.

RIGHT NOW

More than 10 percent of the U.S. Congress has tested positive.

The fallout from the Capitol siege has overshadowed the surging U.S. virus death toll.

As America slogs through this grimmest of winters, there is no relief in the daily tabulations of coronavirus-related deaths: More than 4,400 were reported across the United States on Tuesday, according to a New York Times database, a number once unimaginable.

Yet even as Covid-19 touches thousands of families, the nation is distracted by the political crisis gripping Washington in the last days of the Trump administration.

Tuesday’s death count, which set another daily record, represented at least 1,597 more people than those killed in the terrorist attacks of Sept. 11, 2001.

The U.S. death toll, already the world’s highest by a wide margin, is now about 20,000 shy of 400,000 — only a month after the country crossed the 300,000 threshold, a figure greater than the number of Americans who died fighting in World War II.

But much of the nation’s attention is focused on the fallout from the Capitol siege, prompted in part by President Trump’s efforts to prevent Congress from certifying Joseph R. Biden Jr.’s victory in the November election.

On Wednesday, the House will vote to formally charge Mr. Trump with inciting violence against the country. House lawmakers have formally notified Vice President Mike Pence that they will impeach the president if Mr. Pence and the cabinet do not remove Mr. Trump from power by invoking the 25th Amendment.

As people in the country wait to see how Mr. Trump’s tenure will end, they have also focused on the stories of the five people who were left dead after last week’s rampage — in particular, the death of Brian D. Sicknick, a Capitol Police officer who was overpowered by the mob and struck on the head with a fire extinguisher.

“Brian is a hero,” his brother Ken Sicknick said. “That is what we would like people to remember.”

Each coronavirus death is no less painful to the families and friends who have lost loved ones. Among the latest victims are a revered basketball coach, a travel writer who loved country winters and an architect who had survived the Holocaust.

The health Secretary Alex M. Azar II tried to highlight the urgency of the crisis on Tuesday as the Trump administration said that it would release all available vaccine doses and instructed states to immediately begin inoculating every American 65 and older.

“This next phase reflects the urgency of the situation we face,” he said. “Every vaccine dose that is sitting in a warehouse rather than going into an arm could mean one more life lost or one more hospital bed occupied.”

Recovered coronavirus patients should still get the vaccine, experts say

Research suggests most people who recovered from covid-19 are immune for at least eight months. Yet epidemiologists are largely still urging this population to get the vaccine if it’s their turn in line. 

Official guidance says vaccines should be offered regardless of whether people were previously infected. 

That’s per the Centers for Disease Control and Prevention, which also says the vaccine is safe for people who have had a prior infection. Former CDC director Thomas Frieden said he’d advise most people to get the vaccine, even if they’ve had covid-19.

But Frieden added that he doesn’t think it’s wrong for someone in a low-risk group who’d already had the illness to defer if they thought someone else could use the dose. 

The limits on vaccine supply bolster the argument that recovered people should let others go first. 

As administration of the vaccine bottlenecks across the country, the pressure is on to get the shots in as many arms as quickly as possible. 

Researchers at the University of Colorado Boulder found that prioritizing people who don’t already have natural immunity could allow health officials to get more impact from limited supplies, especially in areas where many people have already been infected, according to a modeling study that has not been peer reviewed

The researchers found that you would need to vaccinate 1 in 5 elderly people in New York to bring death rates down by 73 percent. But you can get the same result vaccinating only 1 in 6 people if you prioritize people who don’t already have antibodies to the virus, according to Kate Bubar, a PhD student in applied mathematics and quantitative biology, who co-authored the study.

And although a previous covid-19 infection isn’t a guarantee of immunity, it’s pretty good protection on its own.Researchers have found that eight months after infection, about 90 percent of patients show lingering, stable immunity. 

Still, risk can vary from person to person.  

“If I were over 70 or otherwise ill, I would certainly take the vaccine even if I’d had [covid-19]. If I were 30 and healthy, I should not be getting it now (unless a health care worker), but if for some reason I did get offered it I would probably decline,” Marc Lipsitch, an infectious-disease specialist at the Harvard T.H. Chan School of Public Health, said in an email.  

Some epidemiologists worry about the logistics of trying to weed out people with natural immunity.

It could complicate the process as health providers are already struggling to get the vaccine distributed quickly. So far around 6.7 million people have been vaccinated, even though 22.1 million doses have been distributed, according to a Washington Post analysis.

Eleanor Murray, an assistant professor of epidemiology at Boston University School of Public Health, worried that trying to verify someone’s past illness would add bureaucratic hurdles. 

“Confirming whether or not someone has had COVID already adds an unnecessary layer of red tape onto vaccine prioritization. Given that the prioritization is designed to get vaccine first to those people who are most likely to get infected and/or get very sick from infection, it makes sense to reduce the barriers to vaccinating this group as much as possible,” Murray said. 

Murray also cautioned that we don’t know how long people’s natural immunity lasts and that it could vary from person to person. This uncertainty may be an added reason to encourage people to get the vaccine.

There’s also a risk that telling people who had covid-19 to hold off on getting the vaccine could end up feeding into anti-vaxxer narratives. Some experts are reluctant to discourage anyone from getting the vaccine if they are eligible, especially given that vaccine hesitancy is widespread. 

There’s already a problem with people being offered the vaccine but not getting it. 

In Santa Rosa County, Fla., only about 40 percent of emergency responders who are eligible to get the vaccine have gotten it or signed up to do so soon. In New York, where around 30 percent of health care workers have declined the vaccine, the state’s Gov. Andrew Cuomo (D) has threatened that anyone who skips a dose now won’t be eligible for a priority vaccine later. 

The low participation rate is concerning, especially at long-term care centers. 

But not everyone who turns down a vaccine is a hardcore anti-vaxxer, Frieden cautions. He says that there is a “movable middle” of people. They aren’t going to be camping out overnight to get an early vaccine, but they may be convincible if costs and other barriers are low. Frieden says it’s crucial to keep a door open for those people, for instance, seeing whether they might be willing to schedule a shot three weeks from now instead of immediately. 

The slow pace of vaccinations has sparked a heated debate over how to stretch supplies.

A vocal group of experts has pushed for officials to consider giving as many people as possible the first dose of the two-shot regimen, even if it means risking a delayed second dose. President-elect Joe Biden has announced his incoming administration will take this approach, sending all doses out the door as quickly as possible instead of holding half back. 

“The plan, announced Friday by the Biden transition team, pivots sharply from the Trump administration’s strategy of holding in reserve roughly half the doses to ensure sufficient supply for people to get a required second shot,” our colleagues reported.

But some epidemiologists, including Frieden, argue that distribution is a bigger problem than supply at this point. Although he said he supports releasing most vaccines, he worries that some of the debates about how to stretch supply are “distractions” from the real obstacles of administration, which he blames in part on a lack of a coordinated federal plan for getting shots into arms. 

“What Operation Warp Speed has generally done is said, ‘We’re responsible for getting the drugs to the states, and after that, it’s their problem,’ ” Frieden said. “That’s a way to facilitate finger pointing; that’s neither a plan nor a solution.” 

Can you spread Covid-19 if you get the vaccine?

https://qz.com/1954762/can-you-spread-covid-19-if-you-get-the-vaccine/?utm_source=YPL

Can you spread Covid-19 if you get the vaccine? — Quartz

We know that the vaccines now available across the world will protect their recipients from getting sick with Covid-19. But while each vaccine authorized for public use can prevent well over 50% of cases (in Pfizer-BioNTech and Moderna‘s case, more than 90%), what we don’t know is whether they’ll also curb transmission of the SARS-CoV-2 virus.

That question is answerable, though—and understanding vaccines’ effect on transmission will help determine when things can go back to whatever our new normal looks like.

The reason we don’t know if the vaccine can prevent transmission is twofold. One reason is practical. The first order of business for vaccines is preventing exposed individuals from getting sick, so that’s what the clinical trials for Covid-19 shots were designed to determine. We simply don’t have public health data to answer the question of transmission yet.

The second reason is immunological. From a scientific perspective, there are a lot of complex questions about how the vaccine generates antibodies in the body that haven’t yet been studied. Scientists are still eager to explore these immunological rabbit holes, but it could take years to reach the bottom of them.

Acting the part

Vaccines work by tricking the immune system into making antibodies before an infection comes along. Antibodies can then attack the actual virus when it enters our systems before they have a chance to replicate enough to launch a full-blown infection. But while vaccines could win an Oscar for their infectious acting job, they can’t get the body to produce antibodies exactly the same way as the real deal.

From what we know so far, Covid-19 vaccines cause the body to produce a class of antibodies called immunoglobulin G, or IgG antibodies, explains Matthew Woodruff, an immunologist at Emory University. IgG antibodies are thugs: They react swiftly to all kinds of foreign entities. They make up the majority of our antibodies, and are confined to the parts of our body that don’t have contact with the outside world, like our muscles and blood.

But to prevent Covid-19 transmission, another type of antibodies could be the more important player. The immune system that patrols your outward-facing mucosal surfaces—spaces like the nose, the throat, the lungs, and digestive tract—relies on immunoglobulin A, or IgA antibodies. And we don’t yet know how well existing vaccines incite IgA antibodies.

“Mucosal immunology is ridiculously complicated,” says Woodruff. “Rather than thinking of immune system as a way to fight off bad actors, it’s really a way for your internal environment to maintain some sort of homeostatic existence with a really dynamic outside world,” as you breathe, eat, drink, and touch your face.

People who get sick and recover from Covid-19 produce a ton of these more-specialized IgA antibodies. Because IgA antibodies occupy the same respiratory tract surfaces involved in transmitting SARS-CoV-2, we could reasonably expect that people who recover from Covid-19 aren’t spreading the virus any more. (Granted, this may also depend on how much of the virus that person was exposed to.)

But we don’t know if people who have IgG antibodies from the vaccine are stopping the virus in our respiratory tracts in the same way. And even if we did, scientists still don’t know how much of the SARS-CoV-2 virus it takes to cause a new infection. So even if we understood how well a vaccine worked to prevent a virus from replicating along the upper respiratory tract, it’d be extremely difficult to tell if that would mean a person couldn’t transmit the disease.

Making it real

Because of all that complication, it’s unlikely that immunological research alone will reveal how well vaccines can prevent Covid-19 transmission—at least, not for years. But there’s another way to tell if a vaccine can stop a person from transmitting a virus to others: community spread.

As more and more people get both doses of a Covid-19 vaccine (and wait a full two weeks after their second dose for maximum immunity to kick in), public health officials can see how fast case counts fall. It may not be a perfect indicator of whether we’re stopping the virus in its tracks—there are many other variables that can slow transmission, including lockdown measures—but for practical purposes, it’ll be good enough to help make public health decisions.

Plus, even though the data we have from clinical trials isn’t perfect, it’s a pretty good indicator that the vaccine at least stops some viral replication. “I can’t imagine how the vaccine would prevent symptomatic infection at the efficacies that [companies] reported and have no impact on transmission,” Woodruff says.

Each of the vaccines granted emergency use in western countries—Moderna, Pfizer-BioNTech, and AstraZeneca—have all shown high efficacy in phase 3 clinical trials. (The Sinopharm and Sinovac vaccines from China and the Bharat Biotech vaccine in India have also been shown to be effective at preventing Covid-19, but aren’t widely approved for use yet.)

Frustratingly, it’s just going to take more time to see if people who got the vaccine are involved in future transmission events. That’s why it’s vital that even after receiving both doses of the Covid-19 vaccine, all individuals wear masks, practice physical distancing, and wash their hands when around those who haven’t been vaccinated—just in case.

How Does the AstraZeneca COVID-19 Vaccine Compare to Pfizer’s and Moderna’s?

covid 19 vaccine

It’s cheaper, easier to distribute, and relies on very different tech than its competitors.

  • AstraZeneca’s COVID-19 vaccine has been approved for emergency use in the United Kingdom, India, and Mexico.
  • Unlike its competitors, AstraZeneca’s vaccine is a modified version of a common cold virus that spreads among chimpanzees.
  • This is the first vaccine of its kind to be approved for human use, but other companies are developing similar tech to fight COVID-19.

The United Kingdom became the first country to approve AstraZeneca’s COVID-19 vaccine for emergency use on Dec. 30, just weeks after Pfizer’s and Moderna’s vaccine candidates received a green light from the Food and Drug Administration in the United States. The approval is another promising sign in the global immunization rollout—especially because this option, developed by Oxford University and biopharmaceutical company AstraZeneca, could be key to reaching people in rural and underfunded areas.

Unlike its competitors, the AstraZeneca COVID-19 vaccine can be stored at higher temperatures, costs less per dose, and uses different technology to immunize people. Although the vaccine hasn’t been approved for use in the U.S. yet, it could reach arms stateside in February at the earliest, The New York Times reports. Here’s what we know about the vaccine so far, and how it stacks up against Pfizer’s and Moderna’s.

How does the AstraZeneca COVID-19 vaccine work?

AstraZeneca’s vaccine uses adenovirus-vectored technology. Translation: It’s a harmless, modified version of a common cold virus that usually only spreads among chimpanzees. This altered virus can’t make you sick, but it carries a gene from the novel coronavirus’ spike protein, the portion of the virus that triggers an immune response. This allows the immune system to manufacture antibodies that work against COVID-19, teaching your body how to respond should you become infected.

In other words, AstraZeneca’s vaccine mimics a COVID-19 infection without its life-threatening side effects, per a release from the company. The reason researchers chose a chimpanzee adenovirus is simple: The modified virus needs to be new to the people being vaccinated—otherwise, the body won’t create those all-important antibodies. Anyone could already have antibodies for a cold spread among humans, but far fewer people have been exposed to a cold spread among chimps.

The Pfizer-BioNTech and Moderna vaccines, meanwhile, rely on mRNA technology, which essentially introduces a piece of genetic code that tricks the body into producing COVID-19 antibodies, no virus required. All three vaccines require two shots spaced about a month apart. Although no adenovirus-vectored vaccine has been approved for human use before, companies like Johnson & Johnson, CanSino, and NantKwest are all working on their own versions.

How does the AstraZeneca vaccine compare to the Moderna and Pfizer vaccines?

Storage and distribution

AstraZeneca’s vaccine is the easiest to transport so far—it can be stored for up to six months between 36 and 46°F, normal refrigerator temperatures. The Moderna and Pfizer options, meanwhile, must be stored at subzero temperatures until they’re ready to be used, at -4°F and -94°F, respectively. (mRNA technology is relatively fragile compared to adenovirus-vectored tech, meaning it must be kept at much lower temperatures to remain effective and stable.)

AstraZeneca’s higher storage temperature could make distribution much easier. “A clinic, a nursing home, or even [regional] health departments may not have freezers that can hold things at -94°F,” says Kawsar Talaat, M.D., an infectious disease doctor, vaccine researcher, and assistant professor in the department of International Health at Johns Hopkins University. Being able to use a typical fridge “allows time for distribution, allows the vaccine time to get to more rural areas, [and allows vaccines] to be kept at a clinic for a longer period of time.”

Cost

The new vaccine also beats its competitors on price: AstraZeneca’s vaccine costs providers about $4 per dose, while Pfizer’s costs $20 and Moderna’s costs $33, Al Jazeera reports. These prices will most likely fluctuate as time goes on and the vaccines evolve.

Efficacy

The two mRNA vaccines have a slight edge in efficacy; both Pfizer and Moderna report being about 95% effective against COVID-19 after the second shot in clinical trials, while AstraZeneca has reported an average efficacy of 70%, and up to 90% if the dosing is adjusted. (For comparison, the annual flu shot is usually between 40 and 60% effective, per the CDC.)

Side effects

All three vaccines’ side effects are similar, including potential injection site pain and flu-like symptoms, including fever, fatigue, headaches, and muscle pain, which are to be expected as your immune system is primed.

Which COVID-19 vaccine is the best?

There’s no “best” vaccine option, as there’s not enough research to confirm that yet. Vaccines aren’t a silver bullet, especially as the pandemic rages on: They must be combined with masks, hand-washing, and social distancing to work as effectively as possible, per the CDC. No matter which COVID-19 vaccine becomes available to you first, you can feel confident in its ability to protect you, as long as you continue being cautious until positive cases, hospitalizations, and deaths are significantly reduced nationwide.

In the meantime, it’s likely “that all the manufacturers are working on making their vaccines more stable at easier-to-manage temperatures,” Dr. Talaat explains. As their formulations change, their pros and cons will, too.

For now, we can be thankful that AstraZeneca’s vaccine is nearing worldwide clearance. “The next generation of vaccines, like AstraZeneca’s, which is kept at refrigerator temperatures, is a major advancement,” Dr. Talaat says. “When you’re talking about distribution to the entire world, it’s much easier to do because we already keep vaccines cold. It’s a lot harder to keep things frozen.”

Two Dead Every Minute: U.S. Covid-19 Cases Surge In 2021

COVID-19 on pace to become the third-leading cause of death in Arizona this  year - The Gila Herald

TOPLINE

In the first week of 2021, roughly two people died from Covid-19 in the U.S. every minute, amid a struggling national vaccination effort, soaring coronavirus cases and the deadliest day of the pandemic yet.

KEY FACTS

According to data from the Covid Tracking Project, 19,418 people died from the disease in the first seven days of 2021.

The U.S. is the country hardest hit by the novel coronavirus — more than 4,000 people died on Thursday, the deadliest day yet of the pandemic, and over 355,000 people have died from the disease since the pandemic began. 

Experts warn that things are likely to get worse before they get better as hospitals across the country are stretched to breaking point — hospitals in LA are reportedly rationing oxygen and many are running out of beds. 

More than 132,000 Americans are currently admitted in hospitals for Covid-19-related care. 

Widespread vaccination, which could help turn the tide against the virus, has failed to gain momentum and the U.S. is way behind its inoculation targets.

The Centers for Disease Control and Prevention says that only 28% of the more than 21 million vaccines it has distributed have been used —  many are reportedly languishing in storage. 

WHAT TO WATCH FOR

President-elect Joe Biden has said he will release all available Covid-19 vaccine doses for immediate use upon taking office, ending Trump’s strategy of saving doses to ensure people have access to a recommended second shot. Some countries, such as the U.K., have decided to space out doses beyond what manufacturers recommend in a bid to provide as many people as possible with some degree of immunity. Experts are torn on the strategy. The U.S. Food and Drug Administration recommends the vaccines are distributed as intended, with a second shot after a 21 or 28 day gap. The British medical regulator, and more recently the World Health Organization, say the second shot can be delayed, although they do not agree on how long this should be.

CRUCIAL QUOTE

Biden warned that the U.S. is falling “far behind” what is needed to control the pandemic. Trump’s approach would take “years,” he said. 

WHAT WE DON’T KNOW

A highly infectious variant of coronavirus, first discovered in the U.K., could be circulating in the U.S.. At least 52 cases have been reported so far. Fortunately, scientists do not believe the variant is able to evade the recently-developed vaccines. 

U.S. surpasses 300,000 daily coronavirus cases, the second alarming record this week

CDC advises 'universal' masks indoors as US Covid deaths again break records  | Coronavirus | The Guardian

The United States on Friday surpassed 300,000 daily coronavirus cases, the second alarming record this week. The number, which roughly equates to the population of St. Louis, Pittsburgh or Cincinnati, comes about two months after the country reported 100,000 coronavirus cases a day for the first time, and one day after more than 4,000 people died from the virus, also a record.

The United States has reported 21.8 million infections and 367,458 deaths.

Storming of Capitol was textbook potential coronavirus superspreader, experts say

https://www.washingtonpost.com/health/2021/01/08/capitol-coronavirus/

Wednesday’s storming of the U.S. Capitol did not just overshadow one of the deadliest days of the coronavirus pandemic — it could have contributed to the crisis as a textbook potential superspreader, health experts warn.

Thousands of Trump supporters dismissive of the virus’s threat packed together with few face coverings — shouting, jostling and forcing their way indoors to halt certification of the election results, many converging from out of town at the president’s urging. Police rushed members of Congress to crowded quarters where legislators say some of their colleagues refused to wear masks as well.

“This was in so many ways an extraordinarily dangerous event yesterday, not only from the security aspects but from the public health aspects, and there will be a fair amount of disease that comes from it,” said Eric Toner, senior scholar at the John Hopkins Center for Health Security.

Experts said that resulting infections will be near-impossible to track, with massive crowds fanning out around the country and few rioters detained and identified. They also wondered if even a significant number of cases would register in a nation overwhelmed by the coronavirus. As Americans shared their shock and anger at the Capitol breach Thursday, the United States reported more than 132,000 people hospitalized with the virus, and more than 4,000 deaths from covid-19, the disease caused by the coronavirus — making it the highest single-day tally yet.

“It is a very real possibility that this will lead to a major outbreak but one that we may or may not be able to recognize,” Toner said. “All the cases to likely derive from this event will likely be lost in the huge number of cases we have in the country right now.”

Trump devotees who flocked to the capital this week said they were unconcerned by the virus, belittling common precautions known to slow its spread and echoing the president’s dismissive attitude toward rising case counts. Trump had encouraged them to gather in defiance of his election loss: “Big protest in D.C. on January 6th,” he tweeted last month. “Be there, will be wild!”

Mike Hebert, 73, drove two days from Kansas to participate. Marching toward the Capitol on Wednesday with an American flag, he said he did not feel the need to wear a face covering.

“I am as scared of the virus as I am of a butterfly,” said Hebert, adding that he is a veteran who was shot twice in Vietnam.

Sisters Courtney and Haley Stone left New York at 11 p.m. to make it to the Capitol by morning so they could quietly counterprotest, draped in Biden gear. “Do you want a mask? I have one,” Haley, 22, asked a Trump supporter, only to be rebuffed.

“Oh, you believe in the mask hoax?” the woman replied.

Health experts predicted Wednesday’s events will contribute to an ongoing case surge in the greater Washington region. The average number of daily new infections in Virginia, Maryland and the District of Columbia reached a record high Thursday, and current covid-19 hospitalizations in the District have risen 19 percent in the past week.

They also noted differences with other large gatherings such as Black Lives Matter protests. Fewer people wore masks during the Capitol protests and riot, they said, and crowds were indoors.

“If you wanted to organize an event to maximize the spread of covid it would be difficult to find one better than the one we witnessed yesterday,” said Jonathan Fielding, a professor at the schools of Public Health and Medicine at UCLA.

“You have the drivers of spreading at a time when we are bearing the heaviest burden of this terrible virus and terrible pandemic,” he said.

Calling in to CBS News Wednesday, Rep. Susan Wild (D-Pa.) described her evacuation to a “crowded” undisclosed location with 300 to 400 other people.

“It’s what I would call a covid superspreader event,” she said. “About half the people in the room are not wearing masks, even though they’ve been offered surgical masks. They’ve refused to wear them.”

She did not identify the lawmakers forgoing face coverings beyond saying they were Republicans, including some freshmen. The Committee on House Administration says it is a “critical necessity” to mask up while indoors at the Capitol, and D.C. has a strict mask mandate.

“It’s certainly exactly the kind of situation that we’ve been told by the medical doctors not to be in,” Wild said.

“We weren’t even allowed to get together with our families for Thanksgiving and Christmas,” she said, “and now we’re in a room with people who are flaunting the rules.”

At least one member of Congress has tested positive since the mob spurred an hours-long lockdown. Newly elected Rep. Jacob LaTurner (R-Kan.) tested positive for the coronavirus late Wednesday evening, according to a statement posted on his Twitter account. It said he is not experiencing symptoms.

“LaTurner is following the advice of the House physician and CDC guidelines and, therefore, does not plan to return to the House floor for votes until he is cleared to do so,” the statement said.

Luke Letlow, a 41-year-old congressman-elect from Louisiana, died of covid-19 last month.

Any infections among members of Congress and their staff will be far easier to contact-trace than those among rioters, said Angela Rasmussen, an affiliate at the Center for Global Health Science and Security at Georgetown University.

“It certainly would have been easier if they were detained by Capitol police and identified, but testing suspects may be something to consider as law enforcement begins to identify them,” Rasmussen said in an email.

She noted that some may try to evade identification and criminal charges, and said she is deeply concerned for the households and communities they might expose.

“I think really rigorous contact tracing of people who are not identified as being present on Capitol grounds will not be possible,” she said.

Nearly 60% of COVID-19 spread may come from asymptomatic spread, model finds

How asymptomatic cases fuelled spread of coronavirus - Times of India

People with COVID-19 who don’t exhibit symptoms may transmit 59 percent of all virus cases, according to a model developed by CDC researchers and published Jan. 7 in JAMA Network Open. 

Since many factors influence COVID-19 spread, researchers developed a mathematical approach to assess several scenarios, varying the infectious period and proportion of transmission for those who never display symptoms according to published best estimates.  

In the baseline model, 59 percent of all transmission came from asymptomatic transmission. That includes 35 percent of new cases from people who infect others before they show symptoms and 24 percent from people who never develop symptoms at all. Under a broad range of values for each of these assumptions, at least 50 percent of new COVID-19 infections were estimated to have originated from exposure to asymptomatic individuals. 

The more contagious variant first identified in the U.K. and since found in six states underscores the importance of the model findings, said Jay Butler, MD, CDC deputy director for infectious diseases and a co-author of the study.

“Controlling the COVID-19 pandemic really is going to require controlling the silent pandemic of transmission from persons without symptoms,” Dr. Butler told The Washington Post. “The community mitigation tools that we have need to be utilized broadly to be able to slow the spread of SARS-CoV-2 from all infected persons, at least until we have those vaccines widely available.”

Whether vaccines stop transmission is still uncertain and was not a scenario addressed in the model.