tag:blogger.com,1999:blog-5848640164815342479.post6407641494327620946..comments2024-03-27T15:36:44.737-07:00Comments on Haq's Musings: Pakistan COVID19 Antibodies Study: 90% of Virus Carriers Have No SymptomsRiaz Haqhttp://www.blogger.com/profile/00522781692886598586noreply@blogger.comBlogger6125tag:blogger.com,1999:blog-5848640164815342479.post-28888853402627000692021-06-29T09:48:07.627-07:002021-06-29T09:48:07.627-07:00#Pfizer and #Moderna #Vaccines Likely to Produce L...#Pfizer and #Moderna #Vaccines Likely to Produce Lasting Immunity Against #COVID19, Study Finds. Most people immunized with the mRNA vaccines may not need boosters, so long as the virus and its variants do not evolve much beyond current forms. #DeltaPlus https://www.nytimes.com/2021/06/28/health/coronavirus-vaccines-immunity.html?smid=tw-share <br /><br />The vaccines made by Pfizer-BioNTech and Moderna set off a persistent immune reaction in the body that may protect against the coronavirus for years, scientists reported on Monday.<br /><br />The findings add to growing evidence that most people immunized with the mRNA vaccines may not need boosters, so long as the virus and its variants do not evolve much beyond their current forms — which is not guaranteed. People who recovered from Covid-19 before being vaccinated may not need boosters even if the virus does make a significant transformation.<br /><br />“It’s a good sign for how durable our immunity is from this vaccine,” said Ali Ellebedy, an immunologist at Washington University in St. Louis who led the study, which was published in the journal Nature.<br /><br />The study did not consider the coronavirus vaccine made by Johnson & Johnson, but Dr. Ellebedy said he expected the immune response to be less durable than that produced by mRNA vaccines.<br /><br /><br />Dr. Ellebedy and his colleagues reported last month that in people who survived Covid-19, immune cells that recognize the virus lie quiescent in the bone marrow for at least eight months after infection. A study by another team indicated that so-called memory B cells continue to mature and strengthen for at least a year after infection.<br /><br />Based on those findings, researchers suggested that immunity might last for years, possibly a lifetime, in people who were infected with the coronavirus and later vaccinated. But it was unclear whether vaccination alone might have a similarly long-lasting effect.<br /><br />Dr. Ellebedy’s team sought to address that question by looking at the source of memory cells: the lymph nodes, where immune cells train to recognize and fight the virus.<br /><br />After an infection or a vaccination, a specialized structure called the germinal center forms in lymph nodes. This structure is an elite school of sorts for B cells — a boot camp where they become increasingly sophisticated and learn to recognize a diverse set of viral genetic sequences.<br /><br />The broader the range and the longer these cells have to practice, the more likely they are to be able to thwart variants of the virus that may emerge.Riaz Haqhttps://www.blogger.com/profile/00522781692886598586noreply@blogger.comtag:blogger.com,1999:blog-5848640164815342479.post-86484890021530875262020-09-17T07:18:32.646-07:002020-09-17T07:18:32.646-07:00Your #Coronavirus Test Is Positive. Maybe It Shoul...Your #Coronavirus Test Is Positive. Maybe It Shouldn’t Be. In 3 sets of data in #Massachusetts , #NewYork and #Nevada , up to 90% of people testing positive for #COVID19 carried barely any virus. Low virus load may not be contagious.- The New York Times<br /><br />https://www.nytimes.com/2020/08/29/health/coronavirus-testing.html<br /><br />Some of the nation’s leading public health experts are raising a new concern in the endless debate over coronavirus testing in the United States: The standard tests are diagnosing huge numbers of people who may be carrying relatively insignificant amounts of the virus.<br /><br />Most of these people are not likely to be contagious, and identifying them may contribute to bottlenecks that prevent those who are contagious from being found in time. But researchers say the solution is not to test less, or to skip testing people without symptoms, as recently suggested by the Centers for Disease Control and Prevention.<br /><br />------------<br /><br />In three sets of testing data that include cycle thresholds, compiled by officials in Massachusetts, New York and Nevada, up to 90 percent of people testing positive carried barely any virus, a review by The Times found.<br /><br />On Thursday, the United States recorded 45,604 new coronavirus cases, according to a database maintained by The Times. If the rates of contagiousness in Massachusetts and New York were to apply nationwide, then perhaps only 4,500 of those people may actually need to isolate and submit to contact tracing.<br /><br />One solution would be to adjust the cycle threshold used now to decide that a patient is infected. Most tests set the limit at 40, a few at 37. This means that you are positive for the coronavirus if the test process required up to 40 cycles, or 37, to detect the virus.<br /><br />Tests with thresholds so high may detect not just live virus but also genetic fragments, leftovers from infection that pose no particular risk — akin to finding a hair in a room long after a person has left, Dr. Mina said.<br /><br />--------------<br /><br />Instead, new data underscore the need for more widespread use of rapid tests, even if they are less sensitive.<br /><br />“The decision not to test asymptomatic people is just really backward,” said Dr. Michael Mina, an epidemiologist at the Harvard T.H. Chan School of Public Health, referring to the C.D.C. recommendation.<br /><br />“In fact, we should be ramping up testing of all different people,” he said, “but we have to do it through whole different mechanisms.”<br /><br />In what may be a step in this direction, the Trump administration announced on Thursday that it would purchase 150 million rapid tests.<br /><br />The most widely used diagnostic test for the new coronavirus, called a PCR test, provides a simple yes-no answer to the question of whether a patient is infected.<br /><br />But similar PCR tests for other viruses do offer some sense of how contagious an infected patient may be: The results may include a rough estimate of the amount of virus in the patient’s body.<br /><br />“We’ve been using one type of data for everything, and that is just plus or minus — that’s all,” Dr. Mina said. “We’re using that for clinical diagnostics, for public health, for policy decision-making.”<br /><br /><br />But yes-no isn’t good enough, he added. It’s the amount of virus that should dictate the infected patient’s next steps. “It’s really irresponsible, I think, to forgo the recognition that this is a quantitative issue,” Dr. Mina said.Riaz Haqhttps://www.blogger.com/profile/00522781692886598586noreply@blogger.comtag:blogger.com,1999:blog-5848640164815342479.post-55977245643629456172020-08-11T18:55:59.814-07:002020-08-11T18:55:59.814-07:00Immune system is like a muscle... you lose it you ...Immune system is like a muscle... you lose it you don’t use it<br /><br />Vaccines for everything from influenza to measles provide partial protection against COVID-19, according to new Mayo Clinic research, suggesting that parents should get children up to date on shots before school this fall, and senior citizens should schedule their vaccinations before the winter flu season.<br /><br />People showed a 28% reduction in COVID-19 risk if they received the PCV13 pneumonia vaccine in the past year compared with those who didn’t, and a 43% reduction if they received the polio vaccine before travels to at-risk locations, the study showed.<br /><br /><br />While the population-based study has limitations and was posted online Tuesday without peer review, Mayo officials said there is little harm in using the results to encourage people to seek shots that are recommended anyway.<br /><br />“Make sure you get your scheduled vaccines,” said Dr. Andrew Badley, an author of the study and a leader of Mayo’s COVID research task force. “Not doing so is not doing everything you can to reduce your risks.”<br /><br /><br />The recommendation comes as Minnesota leaders wrestle with the dilemma of wanting to reopen K-12 schools this fall while facing a rising rate of COVID-19 cases and hospitalizations.<br /><br />Gov. Tim Walz will unveil his school reopening plan Thursday, but he made reference during a press briefing Wednesday to a “decision matrix” that will guide districts on whether to reopen with live classrooms, online sessions or a mix. The guidance is expected to give schools discretion, depending on COVID-19 levels in their communities.<br /><br />“Our guiding principles are to keep our children and our staff in the buildings safe,” Walz said. “Our second goal right behind that is to get our children back in the schools, especially our littlest learners, if at all possible.”<br /><br />The governor on Wednesday highlighted 4 million protective masks that are being distributed to help people comply with Minnesota’s new indoor mask mandate.<br /><br />The Minnesota Department of Health on Wednesday reported nine COVID-19 deaths and 681 infections with the SARS-CoV-2 coronavirus that causes the infectious disease. That brings the state’s totals to 1,589 deaths and 52,947 known infections.<br /><br />The state reported 310 people hospitalized with COVID-19, and 143 of them needing intensive care. Those are both highs for the month of July.<br /><br />Cases have been increasing for weeks, initially among teenagers and young adults but now among older, higher-risk individuals who are more likely to need hospital care, said Kris Ehresmann, state infectious disease director.<br /><br /><br />https://m.startribune.com/non-covid-vaccines-offer-some-covid-protection-mayo-reports/571949932/Riaz Haqhttps://www.blogger.com/profile/00522781692886598586noreply@blogger.comtag:blogger.com,1999:blog-5848640164815342479.post-793567157922681742020-08-11T18:54:56.084-07:002020-08-11T18:54:56.084-07:00One More Reason to Wear a Mask: You’ll Get Less Si...One More Reason to Wear a Mask: You’ll Get Less Sick From COVID-19<br /><br />https://www.ucsf.edu/news/2020/07/418181/one-more-reason-wear-mask-youll-get-less-sick-covid-19<br /><br />As more and more states promote face masks as a way to control the spread of COVID-19, the top-line message has been: wear a mask to protect others. While it’s true that most face masks are more effective in preventing you from launching droplets into the air than breathing in already dispersed droplets – that doesn’t mean masks offer no protection to the wearer.<br /><br />It’s likely that face masks, by blocking even some of the virus-carrying droplets you inhale, can reduce your risk of falling seriously ill from COVID-19, according to Monica Gandhi, MD, an infectious disease specialist at UC San Francisco.<br /><br />“The more virus you get into your body, the more sick you are likely to get,” she said.<br /><br />In the latest wave of infections in the U.S., the wider use of masks may be one factor for the lower death rates – along with more testing, younger patients and better treatments – said Gandhi. A greater proportion of these new cases have been mild or asymptomatic, though more data is needed to see if they track geographically with higher rates of mask-wearing.<br /><br />Worldwide, epidemiological patterns seem to provide a clue. In countries where mask wearing was already commonplace, such as Japan, Taiwan, Thailand, South Korea, and Singapore, and in countries where mask wearing was quickly embraced, such as the Czech Republic, rates of severe illness and death have remained comparatively low.<br /><br />These epidemiological observations are among the evidence that Gandhi and colleagues cite in a paper in the Journal of General Internal Medicine, in which they propose that masks can lead to milder or asymptomatic infections by cutting down on the dose of virus people take in.<br /><br />“Masks can prevent many infections altogether, as was seen in health care workers when we moved to universal masking. We’re also saying that masks, which filter out a majority of viral particles, can lead to a less severe infection if you do get one,” said Gandhi. “If you get infected, but have no symptoms – that’s the best way you can ever get a virus.”<br /><br />The idea that viral dose, also known as viral inoculum, determines the degree of illness is not new, said Gandhi. Descriptions of a dose-mortality curve – how much of a virus is needed to cause death in an animal – were first published in 1938. And after all, the earliest vaccines, which were documented in 16th century China, involved exposing someone to a small amount of smallpox virus to induce mild illness and subsequent immunity.<br /><br />A small number viral particles is more likely to be quelled by the immune system before they can proliferate, said Gandhi.<br /><br />Researchers have studied dose dependency experimentally with other viral infections, like the flu. In a study with healthy volunteers, those who received a higher dose of the influenza A virus developed more severe symptoms.<br /><br />Because the new coronavirus, SARS-CoV-2, is potentially lethal, experiments on masking and disease severity have been necessarily limited to animals. In a hamster study, a surgical mask partition between the cages of infected and uninfected hamsters significantly cut COVID-19 transmission. Fewer hamsters caught the virus and those that did showed milder symptoms.<br /><br />Tale of Two Cruise Ships<br />Gandhi believes the viral inoculum theory helps explain an unusual feature of the new coronavirus – what Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Disease, has called its “protean” manifestations.<br /><br />Early in the year, as COVID-19 spread around the world, infectious disease experts began to notice this strange aspect of the new virus – the extreme variation in its symptoms and severity. Some who tested positive didn’t seem sick at all, some had symptoms of a cold, others lost their sense of taste or developed delirium, and still others suffered severe pneumonia that led to death.<br />Riaz Haqhttps://www.blogger.com/profile/00522781692886598586noreply@blogger.comtag:blogger.com,1999:blog-5848640164815342479.post-13315825643148525752020-07-17T13:22:06.780-07:002020-07-17T13:22:06.780-07:00New Data on T Cells and the #Coronavirus. Paper sh...New Data on T Cells and the #Coronavirus. Paper shows that patients who had SARS coronavirus infection in 2003 still have (17 years later!) a robust T-cell response to the original SARS coronavirus’s N protein. #COVID11 #Immunity https://blogs.sciencemag.org/pipeline/archives/2020/07/15/new-data-on-t-cells-and-the-coronavirus <br /><br />Now comes a new paper in press at Nature. It confirms that convalescent patients from the current epidemic show T-cell responses (mostly CD4+ but some CD8+ as well) to various epitopes of the N (nucleocapsid) protein, which the earlier paper had identified as one of the main antigens as well (along with the Spike and M proteins, among others, with differences between the CD4+ and CD8+ responses as well). Turning to patients who had caught SARS back in 2003 and recovered, it is already known (and worried about) that their antibody responses faded within two or three years. But this paper shows that these patients still have (17 years later!) a robust T-cell response to the original SARS coronavirus’s N protein, which extends an earlier report of such responses going out to 11 years. This new work finds that these cross-react with the new SARS CoV-2 N protein as well. This makes one think, as many have been wondering, that T-cell driven immunity is perhaps the way to reconcile the apparent paradox between (1) antibody responses that seem to be dropping week by week in convalescent patients but (2) few (if any) reliable reports of actual re-infection. That would be good news indeed.<br /><br />And turning to patients who have never been exposed to either SARS or the latest SARS CoV-2, this new work confirms that there are people who nonetheless have T cells that are reactive to protein antigens from the new virus. As in the earlier paper, these cells have a different pattern of reactivity compared to people who have recovered from the current pandemic (which also serves to confirm that they truly have not been infected this time around). Recognition of the nsp7 and nsp13 proteins is prominent, as well as the N protein. And when they looked at that nsp7 response, it turns out that the T cells are recognizing particular protein regions that have low homology to those found in the “common cold” coronaviruses – but do have very high homology to various animal coronaviruses.<br /><br />Very interesting indeed! That would argue that there has been past zoonotic coronavirus transmission in humans, unknown viruses that apparently did not lead to serious disease, which have provided some people with a level of T-cell based protection to the current pandemic. This could potentially help to resolve another gap in our knowledge, as mentioned in that recent post: when antibody surveys come back saying that (say) 95% of a given population does not appear to have been exposed to the current virus, does that mean that all 95% of them are vulnerable – or not? I’ll reiterate the point of that post here: antibody profiling (while very important) is not the whole story, and we need to know what we’re missing.<br /><br />There are still major gaps in our knowledge: how many people have such unknown-coronavirus-induced T-cells? How protective are they? How long-lasting is the T-cell response in people who have been infected with the current SARS CoV-2 virus, and how protective is it in the declining-antibody situation that seems to be common? What sorts of T cell responses will be induced by the various vaccine candidates? We just don’t know yet. But we’re going to find out.Riaz Haqhttps://www.blogger.com/profile/00522781692886598586noreply@blogger.comtag:blogger.com,1999:blog-5848640164815342479.post-28118001000181157092020-07-17T09:38:29.552-07:002020-07-17T09:38:29.552-07:0070℅ of ppl in my circle alone have been infected a...70℅ of ppl in my circle alone have been infected and recovered. Many of my frnds had anti bodies n never felt symptoms. What i feel is we are very near to herd immunity. I cannot find a single household that has not seen infections, which shows we are almost through it.TTnoreply@blogger.com