PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

The Lancet Respiratory Medicine: Past COVID-19 infection does not fully protect young people from reinfection

Study finds that participants who had not previously been infected with SARS-CoV-2 (seronegative) had a five times greater risk of infection than participants who were previously infected, but seropositive people are still at risk of reinfection

2021-04-16
(Press-News.org) A past COVID-19 infection does not completely protect against reinfection in young people, according to an observational study of more than 3,000 healthy members of the US Marines Corps most of whom were aged 18-20 years, published in The Lancet Respiratory Medicine journal.

The authors say that despite previous infection and the presence of antibodies, vaccination is still necessary to boost immune responses, prevent reinfection, reduce transmission, and that young people should take up the vaccine wherever possible.

In the study, between May and November 2020, around 10% (19 out of 189) of participants who were previously infected with SARS-CoV-2 (seropositive) became reinfected, compared with new infections in 50% (1,079 out of 2,247) of participants who had not previously been infected (seronegative).

Although the study was in young, fit, mostly male Marine recruits, the authors believe that the risk of reinfection found in their study will apply to many young people, but that the exact rates of reinfections will not be applicable elsewhere (owing to the crowded living conditions on a military base and close personal contact required for basic training likely contributing to a higher overall infection rate than seen elsewhere). For example, a study of 4 million people in Denmark also found that the risk of infection was five times higher in people who had not before had COVID-19, but they found that only 0.65% of people who had COVID-19 during Denmark's first wave tested positive again during the second wave, compared with 3.3% of people who tested positive after initially being negative [1]. In addition, a preprint study including British healthcare workers found that those who had been not previously infected had a five times higher risk of being reinfected than people who had a past infection [2].

Professor Stuart Sealfon, of Icahn School of Medicine at Mount Sinai, USA, and senior author of the study, says: "As vaccine roll outs continue to gain momentum it is important to remember that, despite a prior COVID-19 infection, young people can catch the virus again and may still transmit it to others. Immunity is not guaranteed by past infection, and vaccinations that provide additional protection are still needed for those who have had COVID-19." [3]

In the study, US Marine Corps recruits completed an unsupervised quarantine at home for two weeks before entering a Marine-supervised quarantine facility for another two weeks. They received antibody tests to establish whether any of the recruits were seropositive (they had previously been infected with SARS-CoV-2 and had antibodies). They were also tested for new SARS-CoV-2 infection at baseline then weeks one and two of the quarantine, and completed a questionnaire including demographic information, risk factors, medical history, and COVID-19 symptoms. Participants were excluded from the study if they tested positive for COVID-19 via PCR test during their supervised quarantine. After quarantine, recruits who did not have COVID-19 entered basic training and were tested for new SARS-CoV-2 infection by PCR tests every two weeks, for six weeks and completed follow up questionnaires about any COVID-19 symptoms.

Recruits who tested positive for a new second COVID-19 infection during the study were isolated and the study team followed up with additional testing. Levels of neutralising antibodies were also taken from subsequently infected seropositive and selected seropositive participants who were not reinfected during the study period.

Of the 2,346 Marines followed long enough for this analysis of reinfection rate, 189 were seropositive and 2,247 were seronegative at the start of the study. Across both groups of recruits, there were 1,098 (45%) new infections during the study. Among the seropositive participants, 19 (10%) tested positive for a second infection during the study. Of the recruits who were seronegative, 1,079 (48%) became infected during the study.

To understand why these reinfections occurred, the authors studied the reinfected and not infected participants' antibody responses. They found that, among the seropositive group, participants who became reinfected had lower antibody levels against the SARS-CoV-2 virus than those who did not become reinfected. In addition, in the seropositive group, neutralising antibodies were less common (neutralising antibodies were detected in 45 (83%) of 54 uninfected, and in six (32%) of 19 reinfected participants during the six weeks of observation).

Comparing new infections between seropositive and seronegative participants, the authors found that viral load (the amount of measurable SARS-CoV-2 virus) in reinfected seropositive recruits was on average only 10 times lower than in infected seronegative participants, which could mean that some reinfected individuals could still have a capacity to transmit infection, but the authors note that this will need further investigation.

In the study, most new COVID-19 cases were asymptomatic - 84% (16 out of 19 participants) in the seropositive group vs 68% (732 out of 1,079 participants) in the seronegative group - or had mild symptoms, and none were hospitalised.

Lt. Dawn Weir, of the Navy Medical Research Centre, USA, says: "Our study shows that some individuals with lower levels of neutralizing antibodies were reinfected, indicating that it is possible that previously infected and recovered people are susceptible to new SARS-CoV-2 infection at a later time. These reinfections may be asymptomatic, as observed in the majority of our participants. This is an important consideration for maintaining U.S. military operational readiness, such as preventing future COVID-19 outbreaks among Marine units or aboard Navy ships. The takeaway message for all young people, including our military service members, is clear - immunity resulting from natural infection is not guaranteed; you still need to be vaccinated even if you have had COVID-19 and recovered." [3]

The authors note some limitations to their study, including that it likely underestimates the risk of reinfection in previously infected individuals because it does not account for people with very low antibody levels following their past infection (in the study there were an unknown number of people in the seronegative group who had previously been infected but who did not have detectable levels of antibodies in their baseline antibody level test).

In the study there was a higher than usual drop-out rate of participants (a total of 566 participants - 34 recruits in the baseline seropositive group and 532 recruits in the baseline seronegative group - who began basic training and did not report for follow up two-weeks later). The study team were not told why any recruit did not return for follow up, but say that this could be a combination of individuals dropping out of the study, those who are transferred off the base for medical reasons, or who were separated from the US Marine Corps.

Lastly, the authors were unable to determine how seropositive recruits contracted their previous SARS-CoV-2 infection and confirm it by PCR test or determine how severe it was and what symptoms they had. They say they also could have missed detectable infections that occurred between the PCR testing every 2 weeks during the study.

Writing in a linked comment, María Velasco of Hospital Universitario Fundación Alcorcón, Spain, said: "This study was conducted in a closed setting but provides some interesting insights regarding the risk of subsequent SARS-CoV-2 infection in the general population or other settings. First, the rate of new SARS-CoV-2 PCR positive results is about 80% lower among seropositive individuals. These data confirm that seropositive individuals have a significant albeit limited protection for new infections [...] Second, the rate of new SARS-CoV-2 PCR detection among seropositive Marines cases is not negligible (1·1 cases per person-year), even in the young and healthy population. Globally, these results indicate that COVID-19 does not provide an almost universal and long-lasting protective immunity such as measles."

She continued: "Efforts must be made to reduce the risk of SARS-CoV-2 transmission from young oligosymptomatic individuals. Results from Letizia et al. suggest that even young individuals with a previous SARS-CoV-2 infection should also be a target of vaccination to avoid a poorly noticed source of transmission."

INFORMATION:

NOTES TO EDITORS This study was funded by the Defense Health Agency and Defense Advanced Research Projects Agency. It was conducted by researchers from the Naval Medical Research Center, Icahn School of Medicine, Mount Sinai, New York, Naval Medical Research Unit SIX, Peru, University of Texas Medical Branch Galveston, University of Vermont and the Naval Medical Readiness and Training Command Beaufort.

The labels have been added to this press release as part of a project run by the Academy of Medical Sciences seeking to improve the communication of evidence. For more information, please see: http://www.sciencemediacentre.org/wp-content/uploads/2018/01/AMS-press-release-labelling-system-GUIDANCE.pdf if you have any questions or feedback, please contact The Lancet press office pressoffice@lancet.com

[1] https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)00575-4/fulltext [2] https://www.medrxiv.org/content/10.1101/2021.01.13.21249642v1 [3] Quote direct from author and cannot be found in the text of the Article

Peer-reviewed / Observational Study / People



ELSE PRESS RELEASES FROM THIS DATE:

Ten reasons why the coronavirus is airborne

2021-04-16
There is consistent, strong evidence that the SARS-CoV-2 virus, which causes COVID-19, is predominantly transmitted through the air, according to a new assessment published today in the medical journal Lancet. Therefore, public health measures that fail to treat the virus as predominantly airborne leave people unprotected and allow the virus to spread, according to six experts from the UK, USA and Canada, including Jose-Luis Jimenez, chemist at the Cooperative Institute for Research in Environmental Sciences (CIRES) and University of Colorado Boulder. "The evidence supporting airborne transmission is overwhelming, and evidence supporting large droplet transmission is almost ...

Protein linked to ALS/Ataxia could play key role in other neurodegenerative disorders

2021-04-15
Neurological disorders are the number one cause of disability in the world, leading to seven million deaths each year. Yet few treatments exist for these diseases, which progressively diminish a person's ability to move and think. Now, a new study suggests that some of these neurological disorders share a common underlying thread. Staufen1, a protein that accumulates in the brains of patients with certain neurological conditions, is linked to amyotrophic lateral sclerosis (ALS), or Lou Gehrig's disease, along with other neurological disorders, including Alzheimer's, Parkinson's, and Huntington's disease, according to University of Utah Health scientists. The findings connect Staufen1 ...

Water crisis took toll on Flint adults' physical, mental health

2021-04-15
ITHACA, N.Y. - Since state austerity policies initiated a potable water crisis seven years ago in Flint, Michigan, public health monitoring has focused on potential developmental deficits associated with lead exposure in adolescents or fetuses exposed in utero. New research from Cornell and the University of Michigan offers the first comprehensive evidence that the city's adult residents suffered a range of adverse physical and mental health symptoms potentially linked to the crisis in the years during and following it, with Black residents affected disproportionately. In a survey of more than 300 residents, 10% reported having been diagnosed by a clinician with elevated ...

Child vaccination rates declined during COVID-19 pandemic

2021-04-15
PASADENA, Calif. -- The numbers of recommended vaccine doses, including measles vaccine, administered to children decreased dramatically after the declaration of a national state of emergency on March 13, 2020, due to the COVID-19 pandemic, according to a Kaiser Permanente study published in Pediatrics. While the decrease was lower and recovered in children under 2 years of age, it was more severe and persistent in older children. "When vaccination rates decline, we worry about an increase in vaccine-preventable diseases that can be harmful to children," said the study's lead author, Bradley Ackerson, MD, a Kaiser Permanente South Bay Medical Center pediatric infectious disease specialist and an investigator with the Kaiser Permanente Southern ...

A method to assess COVID-19 transmission risks in indoor settings

2021-04-15
Two MIT professors have proposed a new approach to estimating the risks of exposure to Covid-19 under different indoor settings. The guideline they developed suggests a limit for exposure time, based on the number of people, the size of the space, the kinds of activity, whether masks are worn, and the ventilation and filtration rates. Their model offers a detailed, physics-based guideline for policymakers, businesses, schools, and individuals trying to gauge their own risks. The guideline, appearing this week in the journal PNAS, was developed by Martin .Z. Bazant, professor of chemical engineering and applied mathematics, and John W. M. Bush, professor of applied mathematics. They stress that one key feature of their model, which has received less attention in existing public-health policies, ...

How the humble woodchip is cleaning up water worldwide

2021-04-15
URBANA, Ill. - Australian pineapple, Danish trout, and Midwestern U.S. corn farmers are not often lumped together under the same agricultural umbrella. But they and many others who raise crops and animals face a common problem: excess nitrogen in drainage water. Whether it flows out to the Great Barrier Reef or the Gulf of Mexico, the nutrient contributes to harmful algal blooms that starve fish and other organisms of oxygen. But there's a simple solution that significantly reduces the amount of nitrogen in drainage water, regardless of the production system or location: denitrifying bioreactors. "Nitrogen pollution from farms is relevant around the world, ...

Study reveals how some antibodies can broadly neutralize ebolaviruses

2021-04-15
LA JOLLA, CA--Some survivors of ebolavirus outbreaks make antibodies that can broadly neutralize these viruses--and now, scientists at Scripps Research have illuminated how these antibodies can disable the viruses so effectively. The insights may be helpful for developing effective therapies. Ebolavirus is a family of often-deadly viruses that includes Ebola virus and many lesser-known viruses such as Bundibugyo virus, Sudan virus and Reston virus. Structural biologists at Scripps Research used electron microscopy techniques to visualize a set of antibodies that target a key site on these viruses called the "glycan cap." Their research showed ...

Novel muscular dystrophy gene connects to a key biological pathway

2021-04-15
MINNEAPOLIS/ST.PAUL (04/15/2021) -- New research from the University of Minnesota Medical School found mutations in a novel gene that may help identify patients with a specific form of muscular dystrophy. The laboratory of Peter B. Kang, MD, the new director of the Paul & Sheila Wellstone Muscular Dystrophy Center at the U of M Medical School, studies the genetics and disease mechanisms of muscular dystrophy. It uses cutting-edge genomic methods to discover disease-causing mutations in patients who cannot find answers via clinical genetic test facilities. The Kang laboratory ...

From smoky skies to a green horizon: Scientists convert fire-risk wood waste into biofuel

From smoky skies to a green horizon: Scientists convert fire-risk wood waste into biofuel
2021-04-15
Reliance on petroleum fuels and raging wildfires: Two separate, large-scale challenges that could be addressed by one scientific breakthrough. Teams from Lawrence Berkeley National Laboratory (Berkeley Lab) and Sandia National Laboratories have collaborated to develop a streamlined and efficient process for converting woody plant matter like forest overgrowth and agricultural waste - material that is currently burned either intentionally or unintentionally - into liquid biofuel. Their research was published recently in the journal ACS Sustainable Chemistry & Engineering. "According to a recent report, by 2050 there will ...

AI pinpoints local pollution hotspots using satellite images

AI pinpoints local pollution hotspots using satellite images
2021-04-15
DURHAM, N.C. - Researchers at Duke University have developed a method that uses machine learning, satellite imagery and weather data to autonomously find hotspots of heavy air pollution, city block by city block. The technique could be a boon for finding and mitigating sources of hazardous aerosols, studying the effects of air pollution on human health, and making better informed, socially just public policy decisions. "Before now, researchers trying to measure the distribution of air pollutants throughout a city would either try to use the limited number of existing monitors or drive sensors around a city in vehicles," said Mike ...

LAST 30 PRESS RELEASES:

Altering cancer treatment dosing could reduce climate impact, study finds

The secret sex life of coral revealed

New deep learning model is ‘game changer’ for measuring embryo development

Smarter foragers do not forage smarter

A unified account of Darwinism’s varieties

Marketers can manage 'feature creep'

Intermittent fasting shows promise in improving gut health, weight management

Scientists identify gene that could lead to resilient ‘pixie’ corn

Utilizing medical assistants to manage patient portal messages shown to support practice and physician efficiency

Study shows clinic continuity associated with reduced hospital and emergency visits

Recognizing the range of experiences among individuals of Latino, Hispanic, and/or Spanish origin is an essential step toward health equity

study reveals decline in reported medicare outpatient procedures by family physicians amid an aging population

COVID-19 pandemic leads to drop in breast cancer screenings, especially among older and racial minority women

Translating the Surgeon General’s framework on social isolation and loneliness to actionable steps in primary care

Point/counterpoint: Is prediabetes overdiagnosed?

Primary care clinics can help low-income families receive nutritional support benefits

The wall of evidence for continuity of care

Parents of children with serious illness from Somali, Hmong, and Latin American communities desire better communication and support in pediatric health care

Primary care can improve hygienic practices while reducing waste

HKUST researchers enhance performance of eco-friendly cooling applications by developing sustainable strategy to manipulate interfacial heat transfer

Variations in medical assistant to primary care clinician staffing ratios may reflect differences in practice ownership and organizational culture

Better disciplinary structures in schools can help reduce hate speech directed against Asian American students

Bringing back an ancient bird

Wistar research identifies mechanisms for selective multiple sclerosis treatment strategy

Fatherhood’s hidden heart health toll

The importance of integrated therapies on cancer: Silibinin, an old and new molecule

Texas A&M-led team creates first global map of seafloor biodiversity activity

Light therapy increases brain connectivity following injury

Power imbalance in health care reveals impact of race and role on team dynamics and DEI efforts

NRG Oncology appoints new vice-chairs for their patient advocate committee

[Press-News.org] The Lancet Respiratory Medicine: Past COVID-19 infection does not fully protect young people from reinfection
Study finds that participants who had not previously been infected with SARS-CoV-2 (seronegative) had a five times greater risk of infection than participants who were previously infected, but seropositive people are still at risk of reinfection