A single dose of vaccine boosts protection against SARS-CoV-2 coronavirus variants, but only in those with previous COVID-19, a study has found.
In those who have not previously been infected and have so far only received one dose of vaccine the immune response to variants of concern may be insufficient.
The findings, published today in the journal Science and led by researchers at Imperial College London, Queen Mary University of London and University College London, looked at immune responses in UK healthcare workers at Barts and Royal Free hospitals following their first dose of the Pfizer/BioNTech vaccine.
They found that people who had previously had mild or asymptomatic infection had significantly enhanced protection against the Kent and South Africa variants, after a single dose of the mRNA vaccine. In those without prior COVID-19, the immune response was less strong after a first dose, potentially leaving them at risk from variants.
Professor Rosemary Boyton, Professor of Immunology and Respiratory Medicine at Imperial College London, who led the research, said: “Our findings show that people who have had their first dose of vaccine, and who have not previously been infected with SARS-CoV-2, are not fully protected against the circulating variants of concern. This study highlights the importance of getting second doses of the vaccine rolled out to protect the population.”
Blood samples were analysed for the presence and levels of immunity against the original strain of SARS-CoV-2, as well as the Kent (B.1.1.7) and South Africa (B.1.351) variants of concern. Along with antibodies — the Y-shaped proteins which stick to the virus and help block or neutralize the threat — the researchers also focused on two types of white blood cell: B-cells, which ‘remember’ the virus; and T cells, which help B cell memory and recognise and destroy cells infected with coronavirus.

En estas instalaciones de Chesterfield, Misuri, billones de bacterias producen diminutos bucles de ADN que contienen genes de coronavirus, la […]

Targeting a pathway that is essential for the survival of certain types of acute myeloid leukaemia could provide a new therapy avenue for patients, the latest research has found.
Researchers from the Wellcome Sanger Institute found that a specific genetic mutation, which is linked with poor prognosis in blood cancer, is involved in the development of the disease when combined with other mutations in mice and human cell lines.
The study, published today (30th April) in Nature Communications, provides a greater understanding of how the loss-of-function mutation in the CUX1 gene leads to the development and survival of acute myeloid leukaemia. The findings suggest that targeting a pathway that is essential for these cancer cells to continue growing could lead to new targeted therapies for some patients.
Acute myeloid leukaemia (AML) is an aggressive blood cancer that affects people of all ages, often requiring months of intensive chemotherapy and prolonged hospital admissions. It typically develops in cells within the bone marrow to crowd out the healthy cells, in turn leading to life-threatening infections and bleeding. Mainstream AML treatments have remained unchanged for decades and fewer than one in three people survive the cancer.
Previously through large-scale DNA sequencing analysis, researchers at the Wellcome Sanger Institute found that loss-of-function mutations in the CUX1 gene on chromosome 7q were seen in several types of cancer, including AML, where it is associated with poor prognosis. However, the role of this gene in AML development is unclear.
In this new study, the team used CRISPR/Cas9 gene-editing technology to show that lack of functioning CUX1 leads to expansion of certain types of blood stem cells, which are defective in a type of regulated cell death known as apoptosis. They found that the loss of CUX1 causes increased expression of the CFLAR gene — which encodes a protein that restrains apoptosis — potentially providing a means for mutated cancer cells to evade cell death and propagate. The researchers showed that targeting CFLAR, or apoptosis evasion pathways in general, could be a possible treatment for those living with this type of AML that is linked to poor prognosis. Currently, there are no clinically approved drugs that target CFLAR.
Dr Saskia Rudat, co-first author and Postdoctoral Fellow at the Wellcome Sanger Institute, said: “By investigating the role of CUX1 further, we now have new insight into how this gene, and the lack of it when mutated, plays a key role in the survival of blood cancer cells. While this mutation doesn’t seem to cause the development of malignant disease on its own, focusing on the pathways involved with CUX1 is a good target for further research.”
Dr Emmanuelle Supper, co-first author and Postdoctoral Fellow at the Wellcome Sanger Institute, said: “By building on our previous analysis, this research has allowed us to gain crucial information about the development of this disease, and would not have been possible without the new and exciting CRISPR/Cas9 and genome sequencing technologies that enable us to investigate genetic weaknesses in cancer. Understanding more about the genetic basis of disease, and how multiple mutations come together to cause blood cancer is vital if we hope to save lives in the future.”
Dr Chi Wong, senior author and Wellcome Clinical Fellow at the Wellcome Sanger Institute and Honorary Consultant Haematologist at Addenbrooke’s Hospital, said: “Acute myeloid leukaemia is a devastating disease, which is currently difficult to treat, especially in cases characterised by genetic lesions such as loss of CUX1 and chromosome 7q deletions. This new study provides evidence that could be used to help develop new targeted treatment for some people living with acute myeloid leukaemia, offering hope for this group of patients who unfortunately are more likely to have a poor prognosis.”
Story Source:
Materials provided by Wellcome Trust Sanger Institute. Note: Content may be edited for style and length.

Gill Castle is on a mission to break down fear and stigma around swimming with a stoma bag.She proudly wears her colostomy pouch, which she needs following a traumatic childbirth – something Gill calls an “unspoken topic of conversation”.To raise awareness of stomas and birth trauma, Gill has spent the winter months swimming in the sea off the coast of north-east England.She told her story to BBC World Service’s Newsday.

SharecloseShare pageCopy linkAbout sharingimage copyrightGetty ImagesOfficials in Delhi have been urged to find more sites for cremations as the city’s morgues and crematoriums are overwhelmed by masses of Covid deaths.A second wave of the virus is ravaging parts of India, with 386,452 new cases reported on Friday – the biggest one-day increase on record for any country.There were another 3,500 deaths nationwide and nearly 400 in Delhi – a record for the capital.The total number of infections in the country has now passed 18 million.The first consignment of emergency medical supplies from the US arrived on Friday, part of what the White House has said will be more than $100m (£72m) worth of support.But oxygen supplies and hospital beds remain in desperately short supply across India, with relatives of Covid patients pleading on social media for help.One senior Delhi police officer said that people were having to cremate family members in crematoriums not designated to take victims of Covid-19.”That’s why we suggested more crematoriums should be set up,” the officer told the NDTV news channel.India’s Health Ministry released detailed guidelines last year for the handling and cremation of people who have died of Covid, with special measures needing to be taken to avoid any potential reinfection.’We try to save a patient until the last breath’US tells citizens to leave India amid Covid crisisWhy can’t Australians get back into their country?India elections go ahead as deaths hit record highIndia’s central government is facing mounting criticism over its handling of the pandemic and its decision to allow large election rallies and religious festivals to go ahead in recent weeks.On Friday, the country’s Supreme Court defended the rights of citizens to express grievances and appeal for help on social media during the current coronavirus crisis, warning actions by the authorities to stop people doing so would be treated as contempt of court. It comes after Twitter was asked to remove a number of posts which were critical of the government earlier this week. The health minister defended the government on Thursday, saying the country’s fatality rate was the lowest in the world and that oxygen supplies were “adequate”. Harsh Vardhan told ANI news agency that oxygen was now “being made available from many sources”, including from abroad, and that storage and cryogenic tankers were also being prepared. A US military plane landed in Delhi on Friday morning, loaded with almost one million rapid Covid tests and 100,000 N95 masks. The White House has said it will donate 15 million N95 masks in total.Jeremy Konyndyk, the executive director of the Covid task force at the US Agency for International Development, told AFP news agency that their first priority was to address India’s most “immediate needs”. The UK also donated ventilators to India earlier this week.However, many experts in India say more is needed. On Tuesday, Mumbai-based Dr Zarir Udwadia told the BBC that the aid being offered was “a drop in an ocean”.What is the latest with vaccinations?On Saturday, all adults above the age of 18 in India will become eligible for vaccination, but there are widespread concerns about the availability of shots. India is the world’s biggest producer of vaccines but does not have enough stock for the estimated 800 million people who will become eligible. So far, fewer than 10% of people in India have had a Covid vaccination.A number of states are reporting shortages of the vaccine. On Thursday, Delhi’s health minister Satyendar Jain said the capital had run out of doses, and that they were waiting for fresh supplies from private companies.image copyrightGetty ImagesIndia’s financial capital, Mumbai, home to more than 20 million people, has suspended its vaccination drive for three days due to “depletion of available vaccines”, the local authority said in a statement. The municipal commissioner of Mumbai, Ashwini Bhide, said on Twitter that the city would reserve current stocks for people aged over 45 years old.This could lead to another crisis. On 1 May, another 40 million people will already be in the queue for their second dose. For the vaccines being administered in India, it is currently recommended that people get their second dose four to eight weeks after the first.

Former England rugby star Mike Tindall has told BBC Breakfast he regretted not pushing his dad more when he was diagnosed with Parkinson’s disease.”I didn’t really understand the process of how it deteriorated and how it could end up at that point”, he said.Read more: Queen mourned husband Philip with bravery – Tindall

Emergent BioSolutions’ C.E.O. announced several executive changes but vigorously defended the company, which is on track for record revenues.WASHINGTON — Executives of Emergent BioSolutions, the Covid-19 vaccine manufacturer that was forced to discard up to 15 million doses because of possible contamination, reported a shake-up in leadership on Thursday and offered the most fulsome defense yet of the company’s performance.While announcing the high-level personnel changes and taking responsibility for the ruined doses, executives nonetheless forecast record revenues this year of nearly $2 billion.Robert Kramer, the chief executive, speaking on a call with investors, said that one senior vice president overseeing manufacturing would depart the company while another executive would go on leave. A third official, Mary Oates, who recently joined Emergent after a long tenure at Pfizer, is now leading the company’s response to a recent federal inspection that found serious flaws at the Baltimore facility that produced the vaccines.The call on Thursday came at a tumultuous time for Emergent, a once-obscure federal contractor that has built a lucrative business selling biodefense products to the government. Production at the Baltimore plant was suspended this month after the discovery that workers had potentially contaminated millions of doses of the Johnson & Johnson vaccine.Addressing these setbacks, Mr. Kramer offered a vigorous defense of the company on Thursday.He took “full responsibility” for the manufacturing problems, acknowledging that the “loss of a batch for a viral contamination is extremely serious, and we treated it as such,” but he also said that Emergent had taken on a “herculean task” in a crisis.Robert Kramer, Emergent’s chief executive, defended the company, saying it had taken on a “herculean task” in a crisis.Joe Andrucyk/Office of Governor Larry Hogan“We were in a situation this time last year where we readily raised our hand, we stepped forward, we ran at this opportunity and the pandemic in a way that few if any other organizations did,” Mr. Kramer said. “I’m proud of the fact that we have stepped up and stepped into this in an aggressive way.”He said the company would submit a response to the Food and Drug Administration in coming days and hoped to “get back into production as quickly as possible.”Despite the manufacturing troubles, Emergent’s chief financial officer, Richard Lindahl, said on the call that the company “delivered strong financial performance” and “significant revenue growth and corresponding profitability” during the first quarter of 2021.The company revised its financial projections, saying it expected a delay in revenue from Covid-19 vaccines, primarily because of the government-requested halt in production.But Emergent still expected to bring in up to $875 million from its manufacturing contracts this year, much of that from Covid-19 vaccine deals. That would amount to nearly half of what the company projects as a record-high annual revenue approaching $2 billion.Last year, Emergent struck deals with the federal government, Johnson & Johnson and AstraZeneca worth up to $1.5 billion, and the company has reported receiving hundreds of millions of dollars under those contracts — even though it has not produced a single dose yet deemed usable by United States regulators.Even as problems mounted at its facility — documented in a series of confidential audits previously reported by The New York Times — the company’s stock price soared. Throughout 2020, Emergent’s founder and chairman, Fuad El-Hibri, cashed in shares and options worth over $42 million, more than he had redeemed in the previous five years combined, a Times investigation found. Mr. Kramer boasted in February that 2020 was “the strongest year in our 22-year history.”This month, shareholders sued Emergent, alleging that executives had misled investors by touting the company’s ability to manufacture Covid-19 vaccines at the Baltimore plant. The manufacturing problems in Baltimore go beyond the loss of the Johnson & Johnson doses. The Times reported this month that Emergent also had to discard millions of AstraZeneca doses for fear of possible contamination.So far, no coronavirus vaccines manufactured by Emergent have been put into the arms of Americans. But the Biden administration recently authorized the release of four million AstraZeneca doses to Mexico and Canada. Officials in both countries said the vaccines were administered there only after testing confirmed their safety, and they assured their citizens that the doses were not affected by quality concerns at Emergent.Earlier this week, with pressure mounting to address the pandemic — including a humanitarian crisis in India — the Biden administration said it also intended to offer other countries access to up to 60 million doses of the AstraZeneca vaccine manufactured by Emergent in Baltimore. But officials said the doses would not be released until regulators determine they are safe.The Baltimore plant is one of two federally designated sites that were supposed to be ready to manufacture vaccines or therapeutics in a public health emergency. In June 2020, the Trump administration awarded Emergent a $628 million contract, mostly to reserve space in Baltimore to produce coronavirus vaccines.In Washington, Emergent is known for its aggressive lobbying and government connections spanning both Democratic and Republican administrations. The company’s board is stocked with former federal officials, and its ranks of lobbyists include former members of Congress.“We’ve been at this for 22 years as a company,” Mr. Kramer said on Thursday’s call, adding that the firm’s relationships with government agencies, including the Biomedical Advanced Research and Development Agency, known as BARDA, which issued the $628 million contract, “remain intact and strong.”In June 2020, shortly after the Trump administration awarded the contract to Emergent, a top official from Operation Warp Speed, the government’s fast-track vaccine initiative, warned that the company lacked enough trained staff and had a record of problems with quality control.A copy of the official’s assessment, obtained by The Times, cited “key risks” in relying on Emergent to handle the production of vaccines developed by both Johnson & Johnson and AstraZeneca at the same plant in Baltimore.Cross-contamination is a “well-known risk” when making two vaccines using live viruses, Mr. Kramer said on Thursday, but the decision to produce both in Baltimore was the government’s. There were layers of safeguards in place, he said, though Emergent believes that they “did not function as anticipated” and that the AstraZeneca virus probably contaminated the Johnson & Johnson batch.“It’s easy to go back and second-guess these decisions that were made in the early stages of the pandemic,” he said. “At the time, no one knew how fast we can get into a clinically viable vaccine, and which candidates would be most successful.”

SharecloseShare pageCopy linkAbout sharingimage copyrightGetty ImagesThe number of deaths related to Covid-19 has passed 400,000 in Brazil, the second-highest in the world, as the country continues to struggle with its vaccination programme.There were 3,001 deaths in 24 hours, after a peak of more than 4,000 was reached at the start of April.The 14-day average of deaths and cases remains high but has seen a slight fall.Congress has opened an inquiry into the government’s handling of the pandemic.President Jair Bolsonaro, who has frequently spoken out against lockdowns, masks and defended unproved drugs as treatment, is facing widespread criticism and his support has plummeted.The outbreak has been fuelled by more transmissible variants of the virus and a lack of co-ordinated national measures. The situation has improved in many areas, including where the health system was on the brink of collapse, after states and cities imposed restrictions, but they are already being eased.Why are so many babies dying of Covid-19 in Brazil? Hunger hits Brazil’s slums amid Covid surgeCovid – what’s gone wrong in Brazil? The rate of occupancy of intensive care unit beds remains at or above 90% in more than a third of the states, according to the health institute Fiocruz, which said the scenario remained “critical”.”[There’s] a tendency of a slight fall but not yet of containment of the epidemic,” the institute said in a report (in Portuguese), warning that the daily number of deaths is likely to remain high.Brazil recorded 100,000 deaths in just 37 days, between March and April, which were the worst months in the country. Only the US has a higher death toll.Since the start of the pandemic, Brazil has had more than 14.5 million cases.Meanwhile, some cities have had to temporarily halt their vaccination programmes amid a shortage of doses. About 13% of the population of 212 million has received at least one dose, according to the Our World in Data tracker.Bolsonaro’s support shrinks as death toll growsBy Mark Lowen, BBC News, São PauloIt is a horrific toll that Brazil may not have reached if vaccines had been bought more quickly and lockdowns imposed. But President Bolsonaro has been reluctant to act – and Brazil is now mourning more than 400,000 dead. Only around 13% of Brazilians have received one vaccine dose and 6% both shots: slow procurement is one of the issues a senate inquiry will now examine, since the government turned down offers of tens of millions of shots from Pfizer last year. The parliamentary commission could recommend the president’s impeachment or even criminal charges.Mr Bolsonaro has been bullish as ever, threatening to send in the army to stop states locking down. And his supporters claim the government could not have purchased vaccine doses sooner, since it was waiting for approval from Brazil’s health regulator.The pandemic has fed Brazil’s deep political polarisation. Mr Bolsonaro is playing to his conservative support base – but polls show it is shrinking as Brazil continues to count its dead.On Tuesday, a Senate commission started an official inquiry into the Bolsonaro government’s response to Covid-19. They have the power to demand documents and call on witnesses to testify, and the findings can be submitted to authorities with the ability to prosecute.The commission will investigate a number of actions, including slow vaccine procurement by the president, his repeated statements downplaying the severity of the virus, and the promotion of scientifically unproven drugs such as hydroxychloroquine.It will also analyse whether the government was negligent in the oxygen crisis in Amazonas state, which was ravaged by a more infectious variant earlier this year, and if indigenous communities in the Amazon were left without assistance, in what critics have described as possible genocide.The inquiry could add to calls for impeachment of the president, though analysts say that is unlikely to happen. But the proceedings and possible revelations can cause serious damage to President Bolsonaro, who is almost certain to run for re-election next year, when his main rival could be former leftist President Luiz Inácio Lula da Silva.President Bolsonaro said he was “not worried” by the inquiry. Since the start of the pandemic, he has opposed any lockdown measures arguing that the damage to the economy would be worse than the effects of the virus itself, a position shared by many of his supporters.In a separate development, the Russian developer of the Sputnik V vaccine has said it will sue Brazil’s health regulator Anvisa for defamation in a row over the product.Anvisa has denied state requests to approve the vaccine for import, and raised concerns about the make up of Sputnik V. At a press conference on Thursday, officials from the regulator condemned the Russian developer’s “grave accusation”.

Your second dose of vaccine gives you more extra protection than you might think. Here’s why you should still get it, even if it’s later than planned.Millions of people have missed their second dose of Covid-19 vaccine. But does it really matter?Yes. Public health officials say that if you’re getting a two-dose vaccine, you should complete both doses for the strongest protection against Covid-19, especially with new variants circulating the globe. From a practical standpoint, missing the second shot could create problems down the road if workplaces, college campuses, airlines and border patrol agents require proof of full vaccination.But many people aren’t getting the message that the second dose matters. More than five million people, or nearly 8 percent of those who got a first shot of the Pfizer or Moderna vaccines, have missed their second doses, according to the most recent data from the Centers for Disease Control and Prevention.The reasons people are missing their second shots vary. Some people say they are worried about side effects, which have widely been reported to be worse after the second dose. Others say second shot appointments have been canceled, and it’s been hard to reschedule. But new research also shows that many people are just confused and wrongly think one shot is enough.Researchers from Cornell University and Boston Children’s Hospital surveyed a representative sample of more than 1,000 Americans in February, and found that 20 percent believed they were strongly protected after just one dose of a two-dose vaccine. (Another 36 percent said they weren’t sure how protected they were.) And among those respondents who had already received at least one shot, 15 percent didn’t remember being told to come back for a second dose. About half didn’t remember anyone telling them that protection was strongest after the second dose, according to the report, published in The New England Journal of Medicine.“Our survey exposed the fact that there is still a lot of confusion about the timing of protection when it comes to getting vaccinated,” said John Brownstein, an epidemiologist and chief innovation officer at Boston Children’s Hospital and a co-author on the research.Adding to the confusion is the fact that some countries are delaying second doses so they can get more people vaccinated more quickly or because they have limited supply of vaccine. Both the Pfizer and Moderna vaccines are what’s known as mRNA vaccines and require two shots, ideally spaced three or four weeks apart. But in some countries, including Britain and Canada, second shots have been delayed by as long as three or four months. While that strategy has worked for countries facing distribution problems or vaccine shortages, Dr. Anthony S. Fauci, the director of the National Institute of Allergy and Infectious Diseases, has repeatedly resisted calls to adopt a one-dose strategy in the United States.The C.D.C. recently reported that a study of health care and emergency workers at high risk for exposure to the coronavirus found a single dose of Pfizer’s or Moderna’s Covid-19 vaccine was 80 percent effective at preventing Covid-19. After the second dose, the vaccines were about 90 percent effective.But vaccine experts say those numbers can mislead people into thinking there’s very little benefit from the second dose, and fail to capture some of the important changes that happen inside the body after a person is fully vaccinated with both doses.“The second dose of mRNA vaccines induces a level of virus neutralizing antibodies about 10-fold greater than the first dose,” said Dr. Paul Offit, a professor at the University of Pennsylvania and a member of the Food and Drug Administration’s vaccine advisory panel. “Also, the second dose induces cellular immunity, which predicts not only longer protection, but better protection against variant strains.”It’s also not clear how long first-dose protection lasts without the boost from a second dose, Dr. Fauci said during a White House press briefing in April.“We have been concerned, and still are, that when you look at the level of protection after one dose, you can say it’s 80 percent, but it’s a somewhat tenuous 80 percent,” Dr. Fauci said. He said there’s concern that more-contagious variants that continue to spread around the globe could partially-evade vaccine-induced antibodies after just one dose. “You’re in a tenuous zone if you don’t have the full impact” of two doses, he said.Although breakthrough infections after vaccination are rare, they do happen. A recent study of 250 people in Israel who were infected after they were partially vaccinated with the Pfizer vaccine — between two weeks after the first dose and one week after the second dose — showed that they were disproportionally infected by B.1.1.7, the variant first identified in Britain. The same study found that in a group of 149 people infected after the second dose of vaccine, eight infections with B.1.351 (the variant first identified in South Africa) occurred between days seven and 13 following the second dose. No breakthrough infections with the South Africa variant were seen 14 days after the second dose. Although it was a small sample, the finding suggested that full vaccination offers more protection against the variants, said Adi Stern, the study’s senior author, a professor at the Shmunis School of Biomedicine and Cancer Research, Tel Aviv University.Another study showing the benefits of full vaccination looked at a group of 91,134 patients who had previously been seen by doctors in the Houston Methodist Hospital system and followed them between December and April. Most were not vaccinated, but 4.5 percent were partially immunized and 25.4 percent were fully immunized. There were 225 deaths from Covid-19 in the group, and 219 (97 percent) were among the unvaccinated. But five deaths (2.2 percent) occurred among the partially immunized. Only one person (0.004 percent) died in the fully immunized group. In that study, full vaccination was 96 protective against hospitalization and 98.7 percent protective against dying from Covid-19. But the partially vaccinated were only 77 percent protected from hospitalization and 64 percent protected from fatal Covid-19.The study’s senior author, Saad B. Omer, director of the Yale Institute for Global Health, said he began the research with a “neutral” view about the benefits of two doses versus a single dose. But he’s now convinced the benefits of a second dose are meaningful.“Given the data from our study and other evidence, it does not make sense for people to skip their second dose,” Dr. Omer said. “When it comes to prevention of deaths through vaccines, the glass is 64 percent full, but wouldn’t you rather have it nearly 100 percent full for such a drastic and irreversible outcome as death?”Beyond the obvious health risks, skipping the second dose also could make your life more complicated if you want to travel or visit facilities that require proof of vaccination. “You will not be considered fully vaccinated,” Dr. Brownstein said. “It may have implications for getting back to normal again. If your vaccine passport or card doesn’t show a complete status, you may not be able to do certain things. You may not be able to get on a plane.”For people who have missed their second dose of the Pfizer or Moderna vaccines, here are answers to some common questions.Is it ever too late to get my second dose? No. If you skipped your dose for any reason, you don’t have to start all over again with another two-dose regimen. The C.D.C. has said that if supplies are low or appointments aren’t available, patients may extend the interval between doses up to six weeks. In Britain, the second dose has been delayed up to three months. Whatever the timing, doctors advise you to get your second dose, even if more time than recommended has passed since your first dose.Where should I go to get my second dose? First, try going back to your original provider — just don’t forget to take the vaccine card you were given after your first dose. At many sites, you can just walk in with your card and receive your second dose if it’s the same location as your first dose. Some state websites specifically allow you to schedule a new second dose appointment. Many CVS and Walgreens sites are also offering second doses to people who got their first shots elsewhere. In fact, stand-alone second doses represented about a quarter of the overall second doses CVS administered last week and 14 percent of those administered in April, said T.J. Crawford, a spokesman for the chain. Just call ahead to make sure they are offering the same vaccine you got the first time.I’m a college student who got my shot on campus. Can I get a second shot in a different state? Pharmacies participating in a federal vaccine distribution program now are setting aside any residency requirements for vaccine recipients. This will allow college students who got their first shot on campus to get their second dose at home.Do people who have tested positive for Covid-19 still need a second shot? Yes. Even if you’ve had Covid-19, you still will get stronger immunity from vaccination. A person’s immune response to a natural infection is highly variable. Some people may produce few antibodies, and natural antibodies seem to be less resistant to variants compared to stronger vaccine-generated antibodies. While it’s not clear how much extra benefit a recovered Covid patient gets from two doses, versus a single dose, you need a second dose to provide proof of full vaccination, should you need it for travel or for work. People who have had Covid-19 in the past are advised to wait about 90 days after infection before getting vaccinated. If you get Covid-19 after your first dose, you may need to adjust your vaccination schedule until you are fully recovered and have approval from your doctor for getting the second shot.What if I’m avoiding the second dose because I’m worried the side effects will be worse? Side effects like fatigue, headache, muscle aches and fever are more common after the second dose of both the Pfizer and Moderna vaccines. But while side effects can be unpleasant, they are manageable, short-lived and a sign that your body is building a strong immune response.Should I get the second shot if I had a severe reaction to the first dose? There are rare cases in which forgoing the second shot is medically advised. The C.D.C. recommends that people skip their second dose if they have a severe allergic reaction after their first shot. The guidance is the same for a milder allergic reaction that develops within four hours, such as hives, wheezing or swelling, even if it doesn’t require emergency care. For most other side effects, though, the agency recommends getting the second dose, unless a doctor or vaccination provider advises otherwise. If you think you had a severe or unusual reaction to your first shot, consult with a physician. You should also check with your doctor if you experience a worrying side effect or side effects that don’t seem to be going away after a few days.Rebecca Robbins