Category: COVID

Categories : COVID UncategorizedTags :

How Effective was Masking for SA in Preventing COVID?

On By ModernMedia
Image by Quicknews

COVID restrictions have finally come to an end altogether in South Africa, as Health Minister Joe Phaahla gazetted a number of changes to the rules, as reported by BusinessTech. This means the end of mask use requirements, social gatherings restrictions and COVID border testing. Prof Shabir Madhi was welcoming of the move in a recent tweet, having criticised SA’s lockdowns as overly harsh and economically damaging. Around the world, many had questioned the widespread use of masks, or their use by some subset of the population, such as children – and even questioned locally by a scientist who argued that it didn’t and wouldn’t work in a South African setting, where people are less adherent to regulations.

Professor Salim Abdool Karim likened such a viewpoint to saying Africans with HIV can’t use ARVs because they didn’t have watches to take them at the right time, reminiscent of “a colonial mentality”.

The case for public mask use is well established. Experiments had shown that even simple cloth masks were moderately effective at hindering the transmission of SARS-CoV-2–containing aerosol particle from infected individuals, though they were less effective at protecting a wearer against infection. Predictably, N95 masks and others are better at doing the job than simple cloth face coverings.

There are no real-world studies for South Africa comparing mask use vs non-mask use as mask wearing was compulsory from the early stages of the outbreak. It would have been downright unethical to ask people to not wear masks, although some people may have had exemptions due to medical conditions or other important reasons. There is a country with good COVID surveillance and a distinct division in mask wearing – the United States. Implementation of mask mandates in the US was down to local authorities, which provides a basis for comparison.

One US study, published in Health Affairs, found that, compared to nonmasking counties, masking counties saw a daily case incidence decline by 25% at four weeks, 35% at six weeks after introduction of masking mandates. The reductions were strongest in Republican-leaning counties, which is notable since Republican voters were less in favour of lockdowns and mask mandates.

Another study found a 16.9% drop in cases four weeks after counties introduced masking mandates. Real-world data also show mask use was effective in preventing infection. A case-and-control study done in California by the CDC showed a 29% drop for surgical mask/respirator use “some of the time” and a 56% drop for “all of the time”.

While a direct comparison between a wealthy country like the US and South Africa as a middle-income country is impossible, it is easy to believe that masking mandates reduced cases by a significant percentage, perhaps saving tens of thousands of lives especially against the country’s possible true COVID death toll of 300 000.

Categories : COVID PaediatricsTags :

Chinese Study Finds Children More Likely to Spread COVID

On By ModernMedia
Photo by Kelly Sikkema on Unsplash

By gaining access to a high quality COVID transmission data from a northern Chinese city which enforced stringent lockdowns, scientists concluded that young people were most responsible for an increase in direct and secondary infections, and also determined that county-wide lockdowns proved effective in limiting the virus’s spread.

The research study, led by Professor of Sociology Zai Liang at University of Albany, was given rare access to patient profiles and contact tracing data from every case accompanying the outbreak of the virus in Shijiazhuang from January to February in 2021. “Because of universal testing and digital tracing, the data are of high quality,” said Prof Liang, who was assisted by Sociology PhD student and lecturer Han Liu. Liu is from Shijiazhuang and has connections with that city’s CDC research centre, which enabled them to get the data.

The two UAlbany researchers, joined by two colleagues from China, published their findings in the Journal of Urban Health.

Prof Liang wrote that while individual-level contact tracing studies on the virus’s transmission and mitigation efforts have been growing, “because of limited testing capacities and risks of infringing on privacy, surveillance data used in individual-level research usually have limited representativeness.” His Shijiazhuang study, whose analysis included 99.52 percent (1028 of 1133) of the transmitted cases in Shijiazhuang, is designed “to fill this gap in the literature.”

The research examined sociodemographic factors including age, gender and socioeconomic status, postulating that “certain sociodemographic characteristics may facilitate the spread of germs by exposing the host to more social contacts.” This would include children interacting in the classroom, females having more contact with their relatives than do males, and less affluent workers working or living in overcrowded settings.

Among the study’s results are:

  • Children 0–17 years old had fewer close contacts than adults, but these led to more secondary infections: 32.1% infected children, 67.9% adults
  • Close contacts of children were 81% more likely to be infected than the contacts of those 18–49
  • Peasant workers, compared to non-manual workers, had 40% more secondary cases from the same neighbourhoods.

Prof Liang wrote, “While children have a low probability of having severe symptoms after being infected by COVID, they can seed the spread in the larger society by infecting their household members and other adults living in their neighbourhoods. These adults can then transmit the disease to their own social contacts. Future studies on how to control within-school infections are therefore urgently needed.”

Another major conclusion of the Shijiazhuang study is that timely non-pharmaceutical interventions, including restrictions on gatherings and school closures, effectively contained further infections via contact reduction, especially when implemented in small areas with the highest caseloads. Liang acknowledged that school closures did have negative ramifications for children’s education and socialisation.

Serendipitous data collection

How did Prof Liang and colleagues obtain comprehensive data not yet publicly available to others? “We heard of this COVID outbreak in this part of northern China early last year, when I was working on a proposal to study COVID. I asked Han Liu if we had connections in that city. It turned out that he is originally from Shijiazhuang and has connections with that city’s CDC research centre.

“The two researchers who collected the data agreed to join us in this effort. I am lucky to ask the right question at the right time.”

Source: University at Albany

Categories : COVID GenderTags :

Females ‘Significantly’ More Likely to Experience Long COVID

On By ModernMedia
Photo by Stephen Andrews on Unsplash

A new study published in Current Medical Research and Opinion has revealed that females are “significantly” more likely to suffer from Long COVID than males and will experience substantially different symptoms.

Long COVID is a syndrome in which complications persist more than four weeks after the initial infection of COVID, sometimes for many months.

In a review of studies, researchers observed females with Long COVID are presenting with a variety of symptoms including ear, nose, and throat issues; mood, neurological, skin, gastrointestinal and rheumatological disorders; as well as fatigue.

Male patients, however, were more likely to experience endocrine disorders such as diabetes and kidney disorders.

“Knowledge about fundamental sex differences underpinning the clinical manifestations, disease progression, and health outcomes of COVID is crucial for the identification and rational design of effective therapies and public health interventions that are inclusive of and sensitive to the potential differential treatment needs of both sexes,” the authors explained.

“Differences in immune system function between females and males could be an important driver of sex differences in Long COVID syndrome. Females mount more rapid and robust innate and adaptive immune responses, which can protect them from initial infection and severity. However, this same difference can render females more vulnerable to prolonged autoimmune-related diseases.”

In their review, researchers gathered a total sample size amounting to 1 393 355 unique individuals.

While the number of participants sounds large, only 35 of the 640 634 total articles in the literature provided sex disaggregated data in sufficient details about symptoms and sequalae of COVID disease to understand how females and males experience the disease differently.

The findings showed that, with the initial onset of COVID, female patients were far more likely to experience mood disorders such as depression, ear, nose, and throat symptoms, musculoskeletal pain, and respiratory symptoms. Male patients, on the other hand, were more likely to suffer from renal disorders.

The authors note that this synthesis of the available literature is among the few to break down the specific health conditions that occur as a result of COVID-related illness by sex. Plenty of studies have examined sex differences in hospitalisation, ICU admission, ventilation support, and mortality. But the research on the specific conditions that are caused by the virus, and its long-term damage to the body, have been understudied when it comes to sex.

“Sex differences in outcomes have been reported during previous coronavirus outbreaks,” the authors added. “Therefore, differences in outcomes between females and males infected with SARS-CoV-2 could have been anticipated. Unfortunately, most studies did not evaluate or report granular data by sex, which limited sex-specific clinical insights that may be impacting treatment.” Ideally, sex disaggregated data should be made available even if it was not the researcher’s primary objective, so other interested researchers can use the data to explore important differences between the sexes.

Greater occupational exposure through traditionally female-dominated jobs may may complicate interpretation the COVID sequelae.

Source: EurekAlert!

Categories : COVIDTags :

Substantially Lower Long COVID Risk from Omicron Infection

On By ModernMedia
SARS-CoV-2 infecting a human cell
Infected cell covered with SARS-CoV-2 viruses. Source: NIAID

Findings from a new study reported in The Lancet has found the risks of developing long COVID are greatly reduced (by ~50% to 75%) as a result of Omicron infection compared to Delta infection.

The study, the first of its kind to report on long COVID risk associated with Omicron, highlights the speed with which app-based health surveillance can provide insights. These have further been shown to be consistent and replicable.

A major strength of the study was the ability to log a wide range of symptoms with the app. Limitations of the self-reported data include no direct testing of infectious variants (here assumed from national data) and no objective measures of illness duration. There was insufficient data to estimate the odds of long COVID in unvaccinated individuals. Finally, to enable swift reporting, the period of assessment of omicron cases was slightly shorter than for the delta variant, and assessment of longer durations of long COVID (eg, >12 weeks) was not possible.

In this case-control observational study, the researchers took self-reported data from the COVID Symptom Study app.

Participants were selected on a positive COVID test after SARS-CoV-2 after vaccination, at least one log per week in the app for at least 28 days after testing positive, and no previous SARS-CoV-2 infections before vaccination. The researchers identified 56 003 UK adults first testing positive between Dec 20, 2021, and March 9, 2022, when the Omicron variant became dominant. Similarly, researchers identified 41 361 UK adult cases first testing positive between June 1, 2021, and Nov 27, 2021, during the period of Delta dominance.

Both symptomatic and asymptomatic infections were considered, and, for the Omicron period, only participants testing positive before Feb 10, 2022, were included, to ensure all participants had at least 28 days for symptom reporting after testing positive. The researchers adjusted for socioeconomic deprivation and other factors.

In both periods, female participation was higher than male participation (55% for Omicron and 59% for Delta cases). Delta and Omicron cases had similar age (mean age 53 years) and prevalence of comorbidities (around 19%). Among Omicron cases, 2501 (4.5%) of 56 003 people experienced long COVID and, among Delta cases, 4469 (10.8%) of 41 361 people experienced long COVID. Cases were stratified by time from vaccination to first infection. They found that, for all vaccine timings, Omicron cases were less likely to experience long COVID, with an odds ratio ranging from 0.24 to 0.50.

However, the researchers noted that the the absolute number of people with long COVID at a certain time depends on the pandemic curve. Considering the UK Omicron peak of more than 350 000 new symptomatic COVID cases per day estimated on March 26, 2022, by the ZOE app model, with 4% of cases being long COVID, future numbers with long COVID will inevitably rise.

Source: The Lancet

Categories : COVIDTags :

Few Patients get ‘Rebound COVID’ after Paxlovid Treatment

On By ModernMedia
Image from Pixabay

Mayo Clinic researchers studied the outcomes of 483 high-risk patients  treated for COVID with a five-day oral regimen of Paxlovid, a combination of nirmatrelvir and ritonavir. Only a handful developed COVID rebound symptoms, something which the researchers say needs further investigation. Their findings appear in the journal Clinical Infectious Diseases.

All of the patients benefited from Paxlovid and recovered, including the patients who developed rebound symptoms, which were generally mild.

“We found that rebound phenomenon was uncommon in this group of patients,” says senior author Aditya Shah, MBBS, an infectious diseases physician and researcher at Mayo Clinic. “The four individuals who experienced rebound [symptoms] represent only 0.8% of the group, and all of them recovered quickly without additional COVID-directed therapy.”

Most of the patients had been vaccinated, and many had received booster vaccinations. The median age was 63. While these patients were high-risk for COVID, none was immunocompromised. Only two patients were admitted to the hospital, and it was for reasons other than COVID.

The study focussed on four patients with rebound symptoms:

  • A 75-year-old man with coronary artery disease who had increased cough and muscle aches 19 days after treatment.
  • A 40-year-old woman with obesity, hypertension and kidney disease who developed fatigue and sore throat six days after treatment.
  • A 69-year-old man with hypertension and obesity who exhibited nasal discharge and cough 10 days following therapy.
  • A 70-year-old man with a history of prostate cancer, obesity, hypertension and high cholesterol, who developed significant sinus congestion 10 days after treatment.

Why did some rebound?

Researchers think one explanation could be that a replication of SARS-CoV-2 could have triggered a secondary immune response, which showed up as mild COVID symptoms. This question could be answered by prospective studies could answer the question. They also note that all four patients with rebound symptoms had many serious health problems known as comorbidities — a factor shown to complicate recoveries. And all four patients had been vaccinated more than 90 days before becoming infected with COVI.

Source: Mayo Clinic

Categories : COVID Lab Tests and ImagingTags :

Rapid Blood Assay to Test for COVID Immunity

On By ModernMedia
Blood sample being drawn
Photo by Hush Naidoo Jade Photography on Unsplash

Researchers have developed a rapid blood assay that measures the strength and duration of an individual’s immunity to SARS-CoV-2. This test will allow population-scale monitoring immunity and vaccine effectiveness. This will help to design revaccination strategies for vulnerable immunosuppressed individuals, according to a study published by the researchers from Mount Sinai in Nature Biotechnology.

The test, which measures the activation of T cells, is performed in under 24 hours and can be scaled up significantly.

“The assay we have created has the ability to measure the population’s cellular immunity and broadly test the efficacy of novel vaccines,” said one of the study’s senior authors, Ernesto Guccione, PhD, Professor at Mount Sinai. “We know that vulnerable populations don’t always mount an antibody response, so measuring T cell activation is critical to assess the full extent of a person’s immunity. Additionally, the emergence of SARS-CoV-2 variants like Omicron, which evade most of the neutralising ability of antibodies, points to the need for assays that can measure T cells, which are more effective against emerging variants of concern.”

Long-term protection from viral infection is mediated by both antibodies and T cell response. Many recent studies point to the importance of determining T cell function in individuals who have recovered from or been vaccinated against COVID to help design vaccination campaigns. However, before this study, measurement of T cell responses has been rarely performed because of the associated technical challenges.

Researchers optimised qPCR-based assays that had the potential to be globally scalable, sensitive, and accurate tests. They then selected the two assays that offered the most scalability. One, the qTACT assay, was accurate and sensitive but had a relatively longer processing time of 24 hours per 200 blood samples, a moderate price, and a medium level of technical skill. The other, the dqTACT assay, was accurate and had a reduced processing time and cost, and required minimal lab experience, making it easy to implement.

The dqTACT assay has recently received the European CE-IVD (in vitro diagnostics) certification, while U.S. Food and Drug Administration and European Medicines Agency clinical validation is ongoing.

“The assays presented here are based on the ability of SARS-CoV-2 T cells to respond to peptides covering different proteins of the virus,” said another senior author, Jordi Ochando, PhD, Assistant Professor at Mount Sinai. “With the possibility of using different peptide pools, our approach represents a flexible strategy that can be easily implemented to detect the presence of T cells responding to different viral proteins. These T cells have an important role in protection from emerging mutant strains, thus immediately gauging the impact that viral mutations might have on cellular immunity.”

Megan Schwarz, a graduate student at Icahn Mount Sinai and first author of the study, added: “Precise measurement of cellular responses underlying virus protection represents a crucial parameter of our levels of immune defence.”

Source: EurekAlert!

Categories : COVID VaccinesTags :

New Vaccines Could Focus on T Cell Response – Without Antibodies

On By ModernMedia
T cell
Scanning Electron Micrograph image of a human T cell. Credit: NIH/NIAID

In a groundbreaking new study, scientists report training T cells to protect against SARS-CoV-2 even without an antibody response. This could open the way to more broadly effective vaccines.

The study’s findings appear in the Proceedings of the National Academy of Sciences.

Current vaccines prompt the creation of antibodies and immune cells that recognise the spike protein. However, these vaccines were developed using the spike protein from an older variant of SARS-CoV-2, reducing their effectiveness against newer variants. Researchers have found that immune cells called T cells tend to recognise parts of SARS-CoV-2 that don’t mutate rapidly. T cells coordinate the immune system’s response and kill cells that have been infected by the SARS-CoV-2 virus.

A vaccine that prompted the body to create more T cells against SARS-CoV-2 could help prevent disease caused by a wide range of variants. To explore this approach, a research team led by Dr Marulasiddappa Suresh from the University of Wisconsin studied two experimental vaccines that included compounds to specifically provoke a strong T-cell response in mice.

The team tested the vaccines’ ability to control infection and prevent severe disease caused by an earlier strain of SARS-CoV-2 as well as by the Beta variant, which is relatively resistant to antibodies raised against earlier strains.

When the researchers vaccinated the mice either either nasally or by injection, the animals developed T cells that could recognise the early SARS-CoV-2 strain and the Beta variant. The vaccines also caused the mice to develop antibodies that could neutralise the early strain. However, they failed to create antibodies that neutralised the Beta variant.

The mice were exposed to SARS-CoV-2 around 3 to 5 months after vaccination. Compared to the controls, vaccinated mice had very low levels of virus in their lungs and were protected against severe illness, which was true of infection with the Beta variant too. This showed that the vaccine provided protection against the Beta variant despite failing to produce effective antibodies against it.

To understand which T cells were providing this protection, the researchers selectively removed different types of T cells in vaccinated mice prior to infection. When they removed CD8 (killer) T cells, vaccinated mice remained well protected against the early strain, although not against the Beta variant. When they blocked CD4 T (helper) cells, levels of both the early strain and Beta variant in the lungs and severity of disease were substantially higher than in vaccinated mice that didn’t have their T cells removed.

These results suggest important roles for CD8 and CD4 T cells in controlling SARS-CoV-2 infection. Current mRNA vaccines do produce some T cells that recognize multiple variants. This may help account for part of the observed protection against severe disease from the Omicron variant. Future vaccines might be designed to specifically enhance this T cell response.

“I see the next generation of vaccines being able to provide immunity to current and future COVID variants by stimulating both broadly-neutralising antibodies and T cell immunity,” Dr Suresh predicted.

Source: National Institutes of Health

Categories : COVIDTags : 1 Comment

Social Distancing in a Shack: Lessons of the Pandemic for SA

On By ModernMedia
Lock with an SA flag

As falling infection rates are beginning to indicate the end of the fifth wave, a paper in the South African Journal of Sciences asks the question – how was it ever feasible for marginalised South Africans to be able to engage in social distancing?

According to a recent seroprevalence study, the vast majority of people in South Africa now have antibodies against COVID in their blood, many acquired through infection and not immunity. The editorial review by Professors Jonathan Jansen and Shabir Madhi, at Stellenbosch University and Wits University, explores the realities of the majority of the population as they struggled under the lockdown.

Just over two years ago, SA garnered praise for instituting one of the harshest lockdowns in the world. In late 2021, while the world panicked over emergence of the Omicron variant, SA led the way with a sharp change in thinking: there was no way now to practically contain COVID with social distancing measures, so it was best to return to as close to normal as possible. This came with an admission that lockdown in SA had failed, and was it doomed from the start with its structural inequalities. SA’s lauded lockdown came with the grotesque spectacle of soldiers forcing people back into their shacks, after all.

Jansen and Madhi considered that a joint UK–SA study found that difficulty adhering to lockdowns or outright noncompliance was largely reported by black Africans in temporary housing. Such conditions entailed lack of savings and access to basic amenities such as private toilets, making lockdown adherence virtually impossible.

Jansen and Madhi observed that inequities were readily apparent, with in-hospital COVID mortality rates being 1.2- to 1.3-fold higher in black African patients, coloured patients and patients of Indian descent compared to white patients. Patients were also 1.5 times more likely to die in public healthcare as opposed to private healthcare, with greater likelihood of ICU admission and mechanical ventilation.

Looking at the impact of gender, voices of experts were mostly (70%) male, Jansen and Madhi noted, and researchers found that COVID had disproportionate impacts on female academics.

The pandemic also brought the ethical question of vaccine mandates, where it was argued that it was permissible for the greater good. But there was a stumbling block of how would consent for enrolment be gained? The SISONKE trial showed that, even among healthcare professionals, informed consent was a problem. Most (71.5%) participated for access to the vaccine, but nearly a third (32%) did not realise that breakthrough infections and adverse events had to be reported two years on.

“Despite the numerous lockdowns and restrictions in South Africa,
the benefits thereof are questionable.”

Overall, studies challenged the benefit of the lockdown. Jansen and Madhi argue that, “Despite the numerous lockdowns and restrictions in South Africa, the benefits thereof are questionable.” Even before the Omicron wave, 73% of South Africans were estimated to have been infected at least once.

SA nevertheless was able to leverage its skills and resources to enter into COVID vaccine manufacture and knowledge sharing, but sustainability ultimately depends on commitment to vaccine programmes in Africa.

Jansen and Madhi stress that the economic costs of the lockdown are ongoing, an by 2021 only 42% of the working population remained employed in SA. Modelling shows that employment might only return to 2018 levels by around 2024 to 2026.

“Consequently, the full societal impact of the COVID-19 pandemic is yet to materialise; and imposing and retaining ongoing regulations under the pretence of trying to prevent SARS-CoV-2 infections, when all indications are that they have failed dismally in the South African context, warrant immediate abandonment.”

Categories : COVIDTags :

End of the Road for Ivermectin as COVID Treatment in South Africa

On By ModernMedia
Stop sign

South Africa’s medicines regulator has officially terminated the special dispensation to use Ivermectin as a treatment for COVID, stating that “there is currently no credible evidence to support a therapeutic role for Ivermectin” in the treatment of the disease.

On Monday 30 May, the South African Health Products Regulatory Authority (SAHPRA) officially withdrew its authorisation [PDF], bringing to end something of a saga which saw vocal proponents pitched against the scientific and regulatory establishment.

The antiparasitic Ivermectin gained considerable notoriety as the COVID pandemic went on, based on preliminary studies that seemed to demonstrate its effectiveness. Pressure born out of desperation for some kind of treatment led to SAHPRA – amidst its own apparent misgivings – granting compassionate use authorisation under strict guidelines in January 2021. Use was allowed under Section 21 guidelines without having to wait for Section 21 authorisation, which was misinterpreted as full authorisation by some media sources.

The social media furore and misinformation surrounding Ivermectin led to dangerous instances of COVID self-treatment, with hospitalisations and even deaths reported.

In its terribly botched response to COVID, Brazil adopted Ivermectin on a mass scale, and essentially became a living laboratory for its effectiveness. Despite even administering Ivermectin as prophylaxis, Brazil’s health system was overwhelmed with COVID patients during the surge caused by the Gamma variant.

Studies turned up scant evidence in favour of Ivermectin’s effectiveness, with serious flaws and even outright data fabrication were picked up in a number of studies that seemed to show a significant benefit – even flying right through the peer review process only to be picked up at a later stage. This lead to a major meta-analysis by Hill et al. showing a effectiveness instead being retracted, which SAHPRA noted in its decision.

Finally, the I-TECH and the Together randomised clinical trials of 2021 showed no effect. Like hydroxychloroquine before it, Ivermectin prescribing was found to be driven by political interests. Thus, Ivermectin quietly disappeared from the media as viable antivirals such as Paxlovid came into the market.

The termination comes after a distinct decline in demand for Ivermectin use in South Africa, with no new applications for importation of unregistered Ivermectin products place since August 2021. SAHPRA also noted a marked decline in the number of health facilities applying for permission to hold bulk stock after August 2021.

Furthermore, no individual named patient applications have been approved since December 2021. Finally, there was little in the way of reporting of outcomes achieved by the treating healthcare providers.

Categories : COVIDTags :

Loss of Smell Went Unnoticed as Delta Wave Symptom

On By ModernMedia
Woman smelling jasmine
Photo by Elly Johnson on Unsplash

The loss of smell and taste with a COVID infection during the delta wave was a prevalent symptom and wasn’t prevented by vaccination, suggests a new study is published in the journal Med.

The small Ohio State University study also found that some people with the earliest COVID infections were continuing to experience loss of these senses months later without realising it.

In participants with active infections during the delta surge, a majority (22 of 25) had been vaccinated. Objective screenings found that 100% were experiencing a diminished or lost sense of smell – but only 54.5% self-reported any problem with odour detection.

“We’re getting this quick communication out as an early warning. We need to continue to take a closer look at COVID infection’s impact on smell and taste,” said Dr Kai Zhao, associate professor of otolaryngology in Ohio State’s College of Medicine and senior author of the study. “Even if COVID doesn’t cause death or hospitalisation, it can have long-lasting effects on some of our sensory functions.

“A lot of people are potentially suffering, which is probably not appreciated by society.”

Data for this study emerged from an earlier project the researchers started to test the use of hard candy as a screening tool for the loss of taste and smell in populations at risk for exposure to the SARS-CoV-2 virus.

As part of that work, the team used an existing objective screening tool to collect sensory function data from 123 never-infected control participants and 65 people who had previous or active COVID infections. During the delta surge, the researchers became alarmed by what they found.

“At that time, there were a lot of speculations about whether smell loss is associated with the delta variant and whether the vaccine could protect against these symptoms. So we decided to do this interim data analysis,” Dr Zhao said.

In addition, about three-fourths of participants whose mostly mild COVID infections had occurred before delta’s dominance reported no ongoing smell and taste losses – however, over half of those participants were found by the objective screening, conducted between 102 and 785 days after their infection diagnosis, to have a loss of smell. 

“Many people who had COVID in the past, probably with the original variants of the virus,  underwent some degree of smell loss, even if they didn’t think they did,” said co-author Susan Travers, professor of biosciences in Ohio State’s College of Dentistry. “This suggests the long-term impact on sensory function isn’t captured by self-reporting.”

Beyond these silent smell and taste losses, there were also people who reported that they hadn’t regained taste or smell function for longer than six months, said first author Kym Man, a graduate student in food science and technology. 

“We’re still collecting data on these long haulers, some of whom have been experiencing smell and taste loss for over a year,” she said. 

Effects on the senses include diminished or complete loss of smell and/or taste, disordered smell and/or taste and, least common, smelling odors that are not present at all. 

The sensory function screenings were conducted with a National Institutes of Health tool consisting of a 9-item scratch-and-sniff odour identifier and an intensity rating of bitterness in a sip of quinine. The odour-detection results were adjusted for age – in general, smell sensitivity declines with age, Dr Zhao said. 

Beyond affecting the quality of life, the loss of smell and taste has health ramifications that include negative effects on nutrition intake and a reduced ability to detect danger – such as a fire or spoiled food.

“The disease’s impact on smell and taste is underreported. This is a public health concern that there may potentially be some broader impacts of COVID that we don’t realise are there,” Dr Zhao said. 

Source: Ohio State University