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The study, which has not yet been peer reviewed for rigor by other scientists, shows that this protection lasts for at least five months and is at a level just below that offered by vaccines from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..

Coronavirus vaccines’ surprising effectiveness

Coronavirus vaccines' surprising effectiveness - Axios

The leading coronavirus vaccines are shaping up to be on par with some of the most effective vaccines in medicine, Axios’ Marisa Fernandez reports.

Why it matters: Vaccines with efficacy rates of about 95% — which both Pfizer and Moderna say they’ve achieved — will be more powerful weapons against the coronavirus than many experts had anticipated.

Flashback: The Food and Drug Administration initially set the bar for a COVID-19 vaccine at 50% efficacy, roughly in line with the seasonal flu vaccine.

  • Some scientists had hoped, in a best-case scenario, it might be as much as 70% effective.
  • “We don’t know yet what the efficacy might be. We don’t know if it will be 50% or 60%. I’d like it to be 75% or more,” the NIH’s Anthony Fauci said in August.

But coming in closer to 95% would put Pfizer and Moderna’s vaccines more in line with the highly effective inoculations against measles, mumps and rubella.

  • Like the MMR and polio vaccines, both prospective COVID-19 products would require two shots to reach that level of efficacy.
  • The third leading contender, being developed by AstraZeneca and Oxford University, would also require two shots. Johnson & Johnson is testing both a single-dose and a two-dose vaccine in simultaneous phase 3 trials.

Yes, but: There’s still a lot we don’t know about these vaccines, including how well they’re likely to work among various demographic groups, and how long the immunity they confer will last.

Nevada man’s COVID-19 reinfection, the first in the US, is ‘yellow caution light’ about risk of coronavirus

https://www.yahoo.com/news/nevada-mans-covid-19-reinfection-223155707.html

COVID-19 reinfection: Nevada man is first confirmed American case

An otherwise healthy 25-year-old Nevada man is the first American confirmed to have caught COVID-19 twice, with the second infection worse than the first.

He has recovered, but his case raises questions about how long people are protected after being infected with the coronavirus that causes the disease, and potentially how protective a vaccine might be.

“It’s a yellow caution light,” said Dr. William Schaffner, an infectious disease expert at the Vanderbilt University School of Medicine in Nashville, Tennessee, who was not involved in the research.

Respiratory infections like COVID-19 don’t provide lifelong immunity like a measles infection. So, Dr. Paul Offit, an infectious disease expert at Children’s Hospital of Philadelphia, said he’s not at all surprised people could get infected twice with the coronavirus, SARS-CoV-2. 

It’s too soon to know whether the man from Washoe County, Nevada, who had no known health problems other than his double infection, was highly unusual or if many people could easily get infected more than once with SARS-CoV-2, Schaffner said.

“There’s hardly an infectious disease doctor in the country who hasn’t encountered a patient who thinks they’ve had a second infection,” he said. “Whether that’s true or not, we don’t know. There are lots of respiratory infections out there.”

How rare is he?

There have been at least 22 documented cases of reinfection worldwide since the start of the pandemic, but it’s unclear how many cases there have actually been, and how common it may be among people who don’t even know they’re infected.

“It could be a one in a million event, we don’t know,” said Akiko Iwasaki, an immunologist at Yale University and an investigator with the Howard Hughes Medical Institute, who wrote a commentary with the study.

With millions of people infected, it’s hard to know if case studies like the new one represent very rare events or the tip of an iceberg, she said. “It’s possible that the vast majority of people are completely protected from reinfection, but we’re not measuring them, because they’re not coming to the hospital.” 

Also, many people don’t know they are infected the first time, so it’s hard to say whether they’re getting re-infected.

In one of the recent cases, a Hong Kong man only knew he was reinfected because it was caught during a routine screening when he returned from outside the country, months after he had cleared an infection and tested negative. 

One reason there may not be more documented cases of reinfection: It’s tough to prove, said Mark Pandori, a pathologist at the University of Nevada, Reno School of Medicine, and senior author on the new study

His team coordinated early in the pandemic with members of the Washoe County Health District to look for repeat infections. They had the benefit of sequencing equipment on campus, as well as microbiologists, he said. And they got lucky finding someone who had been tested both times he was infected and cleared in between. 

Why his infection was worse the second time remains unclear, said Pandori, director of the Nevada State Public Health Laboratory. “I can’t tell you if it tells us anything in particular about the biology of this virus.”

The man caught a slightly different version of the virus the second time, according a genetic analysis of the man’s infections. It’s possible the second version was more dangerous, though there is no evidence of that, or that it was just different enough that his body didn’t recognize it, the paper said.

Implications for vaccination

Iwasaki said the study raises questions about how long immunity lasts after a natural infection. Protection with a vaccine is likely to be quite different, she said.

“Vaccines can be designed to induce much higher levels of antibody and much longer lasting immunity,” she said. Just because the natural infection doesn’t give you protection doesn’t mean the vaccines cannot. It’s a separate issue.”

Offit, also a vaccine expert at the Perelman School of Medicine at the University of Pennsylvania, said he expects protection from vaccines will likely last at least a year or two.

The protection provided by infection or vaccination isn’t 100% perfect until the day it disappears completely, he said. Instead, protection fades gradually, so someone exposed to a huge dose of the virus might get re-infected within months, while others could be protected for years, Offit said.

It’s also possible the Nevada man has an undiagnosed problem with his immune system. “He probably should be seen by an immunologist,” Offit said. 

The length of time an infection will be protective remains one of the key open questions about the virus.

Infected twice, two months apart

The Nevada man, considered an essential worker, started feeling ill in late March, with a sore throat, cough, headache, nausea and diarrhea. His workplace had been hit with an outbreak early in the pandemic, before safety measures like masks could be put in place, said Heather Kerwin, senior epidemiologist at the Washoe County Health District and a co-author on the paper. 

He went for testing on April 18 and his infection with the coronavirus was confirmed.

On April 27, he reported his symptoms had all resolved and he felt fine, but at the time, employees were required to test negative for COVID-19 twice before they would be allowed back to work, Kerwin said. So he remained isolated at home.

A month later, he began feeling poorly again. At the same time, there was an outbreak where one of his parent’s, also an essential worker, was employed, Kerwin said.

On May 31, he went to an urgent care center, reporting fever, headache, dizziness, cough, nausea and diarrhea. On June 5, he went to see a doctor who found his oxygen levels dangerously low and had him hospitalized. Again, the man tested positive for the virus, even though he still had antibodies to the virus in his bloodstream, Kerwin said.

Genetic differences between the viruses responsible for each of his infections suggested he was infected two separate times. The virus doesn’t mutate quickly enough within a single person to explain the differences between the two infections, the researchers found. 

A parent living with the man also caught COVID-19 and was diagnosed on June 5.

Mark Pandori, pathologist
Mark Pandori, pathologist

The paper reports it’s possible the man was reinfected because he was exposed to a higher dose of the virus the second time, perhaps from the family member.

His cough lingered and he suffered from shortness of breath and mental fog, and was on oxygen for six weeks after the second infection, Kerwin said. He has now fully recovered.

Reinfections imply so-called herd immunity cannot be obtained just through natural infection. If natural infection protects for only a few months, then it will be impossible for enough people to be protected simultaneously to reach herd immunity.

The moral of the case study, said co-author Pandori, is even people who already have been sick with COVID-19 need to protect themselves by wearing a mask, avoiding large gatherings, washing hands frequently and maintaining social distance.

“You’re not invulnerable to this,” Pandori said. “In fact, you could get it worse the second time.”

Administration’s new pandemic adviser pushes controversial ‘herd immunity’ strategy, worrying public health officials

https://www.washingtonpost.com/politics/trump-coronavirus-scott-atlas-herd-immunity/2020/08/30/925e68fe-e93b-11ea-970a-64c73a1c2392_story.html?utm_campaign=wp_post_most&utm_medium=email&utm_source=newsletter&wpisrc=nl_most

 

 

One of President Trump’s top medical advisers is urging the White House to embrace a controversial “herd immunity” strategy to combat the pandemic, which would entail allowing the coronavirus to spread through most of the population to quickly build resistance to the virus, while taking steps to protect those in nursing homes and other vulnerable populations, according to five people familiar with the discussions.

The administration has already begun to implement some policies along these lines, according to current and former officials as well as experts, particularly with regard to testing.

The approach’s chief proponent is Scott Atlas, a neuroradiologist from Stanford’s conservative Hoover Institution, who joined the White House earlier this month as a pandemic adviser. He has advocated that the United States adopt the model Sweden has used to respond to the virus outbreak, according to these officials, which relies on lifting restrictions so the healthy can build up immunity to the disease rather than limiting social and business interactions to prevent the virus from spreading.

Sweden’s handling of the pandemic has been heavily criticized by public health officials and infectious-disease experts as reckless — the country has among the highest infection and death rates in the world. It also hasn’t escaped the deep economic problems resulting from the pandemic.

But Sweden’s approach has gained support among some conservatives who argue that social distancing restrictions are crushing the economy and infringing on people’s liberties.

That this approach is even being discussed inside the White House is drawing concern from experts inside and outside the government who note that a herd immunity strategy could lead to the country suffering hundreds of thousands, if not millions, of lost lives.

“The administration faces some pretty serious hurdles in making this argument. One is a lot of people will die, even if you can protect people in nursing homes,” said Paul Romer, a professor at New York University who won the Nobel Prize in economics in 2018. “Once it’s out in the community, we’ve seen over and over again, it ends up spreading everywhere.”

Atlas, who does not have a background in infectious diseases or epidemiology, has expanded his influence inside the White House by advocating policies that appeal to Trump’s desire to move past the pandemic and get the economy going, distressing health officials on the White House coronavirus task force and throughout the administration who worry that their advice is being followed less and less.

Atlas declined several interview requests in recent days. After the publication of this story, he released a statement through the White House: “There is no policy of the President or this administration of achieving herd immunity. There never has been any such policy recommended to the President or to anyone else from me.”

White House communications director Alyssa Farah said there is no change in the White House’s approach toward combatting the pandemic.

“President Trump is fully focused on defeating the virus through therapeutics and ultimately a vaccine. There is no discussion about changing our strategy,” she said in a statement. “We have initiated an unprecedented effort under Operation Warp Speed to safely bring a vaccine to market in record time — ending this virus through medicine is our top focus.”

White House officials said Trump has asked questions about herd immunity but has not formally embraced the strategy. The president, however, has made public comments that advocate a similar approach.

“We are aggressively sheltering those at highest risk, especially the elderly, while allowing lower-risk Americans to safely return to work and to school, and we want to see so many of those great states be open,” he said during his address to the Republican National Convention Thursday night. “We want them to be open. They have to be open. They have to get back to work.”

Atlas has fashioned himself as the “anti-Dr. Fauci,” one senior administration official said, referring to Anthony S. Fauci, the nation’s top infectious-disease official, who has repeatedly been at odds with the president over his public comments about the threat posed by the virus. He has clashed with Fauci as well as Deborah Birx, the White House coronavirus response coordinator, over the administration’s pandemic response.

Atlas has argued both internally and in public that an increased case count will move the nation more quickly to herd immunity and won’t lead to more deaths if the vulnerable are protected. But infectious-disease experts strongly dispute that, noting that more than 25,000 people younger than 65 have died of the virus in the United States. In addition, the United States has a higher number of vulnerable people of all ages because of high rates of heart and lung disease and obesity, and millions of vulnerable people live outside nursing homes — many in the same households with children, whom Atlas believes should return to school.

“When younger, healthier people get the disease, they don’t have a problem with the disease. I’m not sure why that’s so difficult for everyone to acknowledge,” Atlas said in an interview with Fox News’s Brian Kilmeade in July. “These people getting the infection is not really a problem and in fact, as we said months ago, when you isolate everyone, including all the healthy people, you’re prolonging the problem because you’re preventing population immunity. Low-risk groups getting the infection is not a problem.”

Atlas has said that lockdowns and social distancing restrictions during the pandemic have had a health cost as well, noting the problems associated with unemployment and people forgoing health care because they are afraid to visit a doctor.

“From personal communications with neurosurgery colleagues, about half of their patients have not appeared for treatment of disease which, left untreated, risks brain hemorrhage, paralysis or death,” he wrote in The Hill newspaper in May

The White House has left many of the day-to-day decisions regarding the pandemic to governors and local officials, many of whom have disregarded Trump’s advice, making it unclear how many states would embrace the Swedish model, or elements of it, if Trump begins to aggressively push for it to be adopted.

But two senior administration officials and one former official, as well as medical experts, noted that the administration is already taking steps to move the country in this direction.

The Department of Health and Human Services, for instance, invoked the Defense Production Act earlier this month to expedite the shipment of tests to nursing homes — but the administration has not significantly ramped up spending on testing elsewhere, despite persistent shortages. Trump and top White House aides, including Atlas, have also repeatedly pushed to reopen schools and lift lockdown orders, despite outbreaks in several schools that attempted to resume in-person classes.

The Centers for Disease Control and Prevention also updated its testing guidance last week to say that those who are asymptomatic do not necessarily have to be tested. That prompted an outcry from medical groups, infectious-disease experts and local health officials, who said the change meant that asymptomatic people who had contact with an infected person would not be tested. The CDC estimates that about 40 percent of people infected with covid-19, the disease caused by the coronavirus, are asymptomatic, and experts said much of the summer surge in infections was due to asymptomatic spread among young, healthy people.

Trump has previously floated “going herd” before being convinced by Fauci and others that it was not a good idea, according to one official.

The discussions come as at least 5.9 million infections have been reported and at least 179,000 have died from the virus this year and as public opinion polls show that Trump’s biggest liability with voters in his contest against Democratic nominee Joe Biden is his handling of the pandemic. The United States leads the world in coronavirus cases and deaths, with far more casualties and infections than any other developed nation.

The nations that have most successfully managed the coronavirus outbreak imposed stringent lockdown measures that a vast majority of the country abided by, quickly ramped up testing and contact tracing, and imposed mask mandates.

Atlas meets with Trump almost every day, far more than any other health official, and inside the White House is viewed as aligned with the president and White House Chief of Staff Mark Meadows on how to handle the outbreak, according to three senior administration officials.

In meetings, Atlas has argued that metropolitan areas such as New York, Chicago and New Orleans have already reached herd immunity, according to two senior administration officials. But Birx and Fauci have disputed that, arguing that even cities that peaked to potential herd immunity levels experience similar levels of infection if they reopen too quickly, the officials said.

Trump asked Birx in a meeting last month whether New York and New Jersey had reached herd immunity, according to a senior administration official. Birx told the president there was not enough data to support that conclusion.

Atlas has supporters who argue that his presence in the White House is a good thing and that he brings a new perspective.

“Epidemiology is not the only discipline that matters for public policy here. That is a fundamentally wrong way to think about this whole situation,” said Avik Roy, president of the Foundation for Research on Equal Opportunity, a think tank that researches market-based solutions to help low-income Americans. “You have to think about what are the costs of lockdowns, what are the trade-offs, and those are fundamentally subjective judgments policymakers have to make.”

It remains unclear how large a percentage of the population must become infected to achieve “herd immunity,” which is when enough people become immune to a disease that it slows its spread, even among those who have not been infected. That can occur either through mass vaccination efforts, or when enough people in the population become infected with coronavirus and develop antibodies that protect them against future infection.

Estimates have ranged from 20 percent to 70 percent for how much of a population would need to be infected. Soumya Swaminathan, the World Health Organization’s chief scientist, said given the transmissibility of the novel coronavirus, it is likely that about 65 to 70 percent of the population would need to become infected for there to be herd immunity.

With a population of 328 million in the United States, it may require 2.13 million deaths to reach a 65 percent threshold of herd immunity, assuming the virus has a 1 percent fatality rate, according to an analysis by The Washington Post.

It also remains unclear whether people who recover from covid-19 have long-term immunity to the virus or can become reinfected, and scientists are still learning who is vulnerable to the disease. From a practical standpoint, it is also nearly impossible to sufficiently isolate people at most risk of dying due to the virus from the younger, healthier population, according to public health experts.

Atlas has argued that the country should only be testing people with symptoms, despite the fact that asymptomatic carriers spread the virus. He has also repeatedly pushed to reopen schools and advocated for college sports to resume. Atlas has said, without evidence, that children do not spread the virus and do not have any real risk from covid-19, arguing that more children die of influenza — an argument he has made in television and radio interviews.

Atlas’s appointment comes after Trump earlier this summer encouraged his White House advisers to find a new doctor who would argue an alternative point of view from Birx and Fauci, whom the president has grown increasingly annoyed with for public comments that he believes contradict his own assertions that the threat of the virus is receding. Advisers sought a doctor with Ivy League or top university credentials who could make the case on television that the virus is a receding threat.

Atlas caught Trump’s attention with a spate of Fox News appearances in recent months, and the president has found a more simpatico figure in the Stanford doctor for his push to reopen the country so he can focus on his reelection. Atlas now often sits in the briefing room with Trump during his coronavirus news conferences, even as other doctors do not. He has given the president somewhat of a medical imprimatur for his statements and regularly helps draft the administration’s coronavirus talking points from his West Wing office as well as the slides that Trump often relies on for his argument of a diminishing threat.

Atlas has also said he is unsure “scientifically” whether masks make sense, despite broad consensus among scientists that they are effective. He has selectively presented research and findings that support his argument for herd immunity and his other ideas, two senior administration officials said.

Fauci and Birx have both said the virus is a threat in every part of the country. They have also put forward policy recommendations that the president views as too draconian, including mask mandates and partial lockdowns in areas experiencing surges of the virus.

Birx has been at odds with Atlas on several occasions, with one disagreement growing so heated at a coronavirus meeting earlier this month that other administration officials grew uncomfortable, according to a senior administration official.

One of the main points of tension between the two is over school reopenings. Atlas has pushed to reopen schools and Birx is more cautious.

“This is really unfortunate to have this fellow Scott Atlas, who was basically recruited to crowd out Tony Fauci and the voice of reason,” said Eric Topol, a cardiologist and head of the Scripps Research Translational Institute in San Diego. “Not only do we not embrace the science, but we repudiate the science by our president, and that has extended by bringing in another unreliable misinformation vector.”

 

“Immunity passports” in the context of COVID-19

https://www.who.int/news-room/commentaries/detail/immunity-passports-in-the-context-of-covid-19

Charu Kaushic (@CKaushic) | Twitter

Scientific Brief

WHO has published guidance on adjusting public health and social measures for the next phase of the COVID-19 response.1 Some governments have suggested that the detection of antibodies to the SARS-CoV-2, the virus that causes COVID-19, could serve as the basis for an “immunity passport” or “risk-free certificate” that would enable individuals to travel or to return to work assuming that they are protected against re-infection. There is currently no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection.

 

The measurement of antibodies specific to COVID-19

The development of immunity to a pathogen through natural infection is a multi-step process that typically takes place over 1-2 weeks. The body responds to a viral infection immediately with a non-specific innate response in which macrophages, neutrophils, and dendritic cells slow the progress of virus and may even prevent it from causing symptoms. This non-specific response is followed by an adaptive response where the body makes antibodies that specifically bind to the virus. These antibodies are proteins called immunoglobulins. The body also makes T-cells that recognize and eliminate other cells infected with the virus. This is called cellular immunity. This combined adaptive response may clear the virus from the body, and if the response is strong enough, may prevent progression to severe illness or re-infection by the same virus. This process is often measured by the presence of antibodies in blood.

WHO continues to review the evidence on antibody responses to SARS-CoV-2 infection.2-17 Most of these studies show that people who have recovered from infection have antibodies to the virus. However, some of these people have very low levels of neutralizing antibodies in their blood,4 suggesting that cellular immunity may also be critical for recovery. As of 24 April 2020, no study has evaluated whether the presence of antibodies to SARS-CoV-2 confers immunity to subsequent infection by this virus in humans.

Laboratory tests that detect antibodies to SARS-CoV-2 in people, including rapid immunodiagnostic tests, need further validation to determine their accuracy and reliability. Inaccurate immunodiagnostic tests may falsely categorize people in two ways. The first is that they may falsely label people who have been infected as negative, and the second is that people who have not been infected are falsely labelled as positive. Both errors have serious consequences and will affect control efforts. These tests also need to accurately distinguish between past infections from SARS-CoV-2 and those caused by the known set of six human coronaviruses. Four of these viruses cause the common cold and circulate widely. The remaining two are the viruses that cause Middle East Respiratory Syndrome and Severe Acute Respiratory Syndrome. People infected by any one of these viruses may produce antibodies that cross-react with antibodies produced in response to infection with SARS-CoV-2.

Many countries are now testing for SARS-CoV-2 antibodies at the population level or in specific groups, such as health workers, close contacts of known cases, or within households.21 WHO supports these studies, as they are critical for understanding the extent of – and risk factors associated with – infection.  These studies will provide data on the percentage of people with detectable COVID-19 antibodies, but most are not designed to determine whether those people are immune to secondary infections.

 

Other considerations

At this point in the pandemic, there is not enough evidence about the effectiveness of antibody-mediated immunity to guarantee the accuracy of an “immunity passport” or “risk-free certificate.” People who assume that they are immune to a second infection because they have received a positive test result may ignore public health advice. The use of such certificates may therefore increase the risks of continued transmission. As new evidence becomes available, WHO will update this scientific brief.