H5N1

Comparison of the characteristics, morbidity, and mortality of COVID-19 and seasonal influenza: A nationwide, population-based retrospective cohort study

Via The Lancet Respiratory Medicine: Comparison of the characteristics, morbidity, and mortality of COVID-19 and seasonal influenza: a nationwide, population-based retrospective cohort study. The summary:

Background 

To date, influenza epidemics have been considered suitable for use as a model for the COVID-19 epidemic, given that they are respiratory diseases with similar modes of transmission. However, data directly comparing the two diseases are scarce. 

Methods 

We did a nationwide retrospective cohort study using the French national administrative database (PMSI), which includes discharge summaries for all hospital admissions in France. All patients hospitalised for COVID-19 from March 1 to April 30, 2020, and all patients hospitalised for influenza between Dec 1, 2018, and Feb 28, 2019, were included. The diagnosis of COVID-19 (International Classification of Diseases [10th edition] codes U07.10, U07.11, U07.12, U07.14, or U07.15) or influenza (J09, J10, or J11) comprised primary, related, or associated diagnosis. Comparisons of risk factors, clinical characteristics, and outcomes between patients hospitalised for COVID-19 and influenza were done, with data also stratified by age group. 

Findings 

89 530 patients with COVID-19 and 45 819 patients with influenza were hospitalised in France during the respective study periods. The median age of patients was 68 years (IQR 52–82) for COVID-19 and 71 years (34–84) for influenza. Patients with COVID-19 were more frequently obese or overweight, and more frequently had diabetes, hypertension, and dyslipidaemia than patients with influenza, whereas those with influenza more frequently had heart failure, chronic respiratory disease, cirrhosis, and deficiency anaemia. 

Patients admitted to hospital with COVID-19 more frequently developed acute respiratory failure, pulmonary embolism, septic shock, or haemorrhagic stroke than patients with influenza, but less frequently developed myocardial infarction or atrial fibrillation. In-hospital mortality was higher in patients with COVID-19 than in patients with influenza (15 104 [16·9%] of 89 530 vs 2640 [5·8%] of 45 819), with a relative risk of death of 2·9 (95% CI 2·8–3·0) and an age-standardised mortality ratio of 2·82. 

Of the patients hospitalised, the proportion of paediatric patients (<18 years) was smaller for COVID-19 than for influenza (1227 [1·4%] vs 8942 [19·5%]), but a larger proportion of patients younger than 5 years needed intensive care support for COVID-19 than for influenza (14 [2·3%] of 613 vs 65 [0·9%] of 6973). In adolescents (11–17 years), the in-hospital mortality was ten-times higher for COVID-19 than for influenza (five [1·1% of 458 vs one [0·1%] of 804), and patients with COVID-19 were more frequently obese or overweight. 

Interpretation 

The presentation of patients with COVID-19 and seasonal influenza requiring hospitalisation differs considerably. Severe acute respiratory syndrome coronavirus 2 is likely to have a higher potential for respiratory pathogenicity, leading to more respiratory complications and to higher mortality. In children, although the rate of hospitalisation for COVID-19 appears to be lower than for influenza, in-hospital mortality is higher; however, low patient numbers limit this finding. These findings highlight the importance of appropriate preventive measures for COVID-19, as well as the need for a specific vaccine and treatment.

Analysis: Could COVID-19 knock out flu in Europe this winter?

Via Reuters: Analysis: Could COVID knock out flu in Europe this winter? Excerpt:

PARIS (Reuters) - As Europeans brace for a grim winter with the threat of rising COVID-19 infections, minimal numbers of flu cases recorded so far point to a possible silver lining.

Data available for Europe since the beginning of October, when flu case numbers usually start to ramp up, mirror shallow figures seen in the Southern Hemisphere earlier this year. 

Some doctors say a combination of lockdowns, mask wearing and handwashing appear to have hampered transmission of the flu, while warning that the data should be treated with caution because the peak of the season is weeks or even months away.  

According to Flu News Europe, a joint monitoring platform of the European Centre for Disease Prevention and Control and the World Health Organization which collects samples in 54 European regions, only one person was diagnosed with flu out of 4,433 sentinel tests during Sept. 28-Nov. 22.  

This sentinel-source data -- case figures collated by national health authorities based on samples taken by a range of community doctors -- translates into a positivity rate of 0.02%, well below a 10% threshold that the WHO considers to be “epidemic” when it comes to flu. 

At the same time last year, this percentage stood at 15%. 

While scientists caution that the coronavirus pandemic has constrained testing for flu, the low sentinel rate so far will provide some relief to governments and health authorities, which had feared a potentially lethal “twindemic” of COVID-19 and flu that could overwhelm hospitals during the winter. 

“In any given typical year, we should be witnessing hundreds of influenza cases at this stage in Europe and beyond,” Bruno Lina, a senior virologist with Hospices Civils de Lyon, which runs 13 hospitals in France’s third-largest city, told Reuters. 

“Steps adopted to prevent transmission of COVID-19 are very efficient against influenza and other respiratory viruses.”

Double threat of COVID-19 and influenza

A news item in The Lancet Respiratory Medicine: Double threat of COVID-19 and influenza. Excerpt:

At the time of publication, it looks like the second wave of COVID-19 is well underway in Europe. The weekly tally of new cases has been steadily rising for more than 2 months, but the past few weeks have seen accelerated transmission. Cases have also been trending upwards in the USA. Oct 14, 2020, saw the nation register the highest number of new cases of COVID-19 since Aug 7. In general, countries are much better prepared than they were when severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) first exploded onto the scene. But October also marks the beginning of the flu season in the northern hemisphere. If both viruses surge simultaneously, even the best resourced health-care systems would be hard pressed to cope. 

The southern hemisphere avoided such an eventuality. Their recently concluded flu season was exceptionally mild. It is possible that behind the apparently low caseload lay thousands of undetected patients. Perhaps influenza testing fell away as countries concentrated their resources on COVID-19. Large numbers of people might have struggled through bouts of influenza at home, hidden from the statisticians. In a briefing to the media on June 15, 2020, WHO director-general Tedros Adhanom Ghebreyesus noted that “influenza surveillance has either been suspended or is declining in many countries, and there has been a sharp decline in sharing of influenza information and viruses because of the COVID-19 pandemic”. He added that “compared with the last 3 years, we've seen a dramatic decrease in the number of specimens tested for influenza globally”. 

Nonetheless, it is hard to imagine that the precautions against SARS-CoV-2 did not prove even more effective against influenza, a less contagious virus. By this time last year, Australia had confirmed 298 120 cases of influenza and 812 deaths. Thus far this year, the country has registered 21 156 cases and just 36 deaths. “While influenza testing in Australia and New Zealand is maintained or even increased, very few influenza viruses were detected”, stated WHO, in their most recent influenza update. 

But whether this will translate to an equivalently mild flu season in the northern hemisphere, where the public is becoming increasingly tired of control measures, remains to be seen. The UK, for example, is unlikely to replicate the kind of lockdown it enacted in the early part of the pandemic. 

“I think we are probably going to see a great deal more COVID-19 in the USA over the next few months, as people move indoors and we continue without any concerted approach to containment”, said Daniel Salmon, director of Johns Hopkins Institute for Vaccine Safety (Baltimore, USA). 

“But we should expect the social distancing and other measures to have some effect on influenza transmission, even if they are not followed across the board.”

Flu News Europe, week 41

An update from Flu News Europe:

Weekly influenza overview

Week 41/2020 (5 October–11 October 2020)    

• Influenza activity remained at interseasonal levels.  

• None of 107 sentinel specimens tested for influenza viruses in week 41 were positive. 

• Of 4 673 non-sentinel specimens tested, 11 were positive (4 A unsubtyped, 3 A(H3), 2 A(H1)pdm09 and 2 type B viruses were not ascribed to a lineage). 

• There were no hospitalized laboratory-confirmed influenza cases for week 41/2020.   

• The novel coronavirus disease 2019 (COVID-19) pandemic has affected healthcare presentations and testing capacities of countries and areas in the Region, which negatively impacted reporting of influenza epidemiologic and virologic data during the 2019-2020 season. It is not unusual for influenza activity to be low at this time of year but, if the COVID-19 pandemic continues, influenza data we present, notably in terms of seasonal patterns, will need to be interpreted with caution.  

Flu News Europe: Final report for 2019-20 season

Via Flu News Europe, a wrap-up. Excerpt:

Weeks 21-39/2020 (18 May - 27 September 2020)  

• This is the final report for the 2019-2020 influenza season. 

• Influenza activity has been at inter-seasonal levels over the period of this report.  

• Of 1 523 sentinel specimens tested for influenza viruses in weeks 21-39, 3 tested positive (one each of A(H3N2), B/Victoria lineage and type B no lineage ascribed).   

• The novel coronavirus disease 2019 (COVID-19) pandemic has affected healthcare presentations and testing capacities of Member States in the Region, which negatively impacted reporting of influenza epidemiologic and virologic data. Therefore, the data we present, notably in terms of seasonal patterns, must be interpreted with caution.   

• Weekly reporting for the 2020-2021 influenza season will start in week 40 with the first analysis being published on 10 October 2020. 

COVID-19 testing in the UK

An editorial in The Lancet Respiratory Medicine: COVID-19 testing in the UK.

During the past week, the UK has seen an alarming rise in COVID-19 cases. With a second wave of infections approaching, there is a need to adequately respond with a robust test and trace system. However, neither the testing nor the tracing system currently in place is prepared for the substantial increase in demand for tests. As autumn begins, we face the co-occurrence of schools and universities reopening, people returning to work, and the approach of the influenza season. 

Children have now returned to school, where the risk of becoming ill increases. As soon as a child shows any symptoms that could indicate COVID-19, they are sent home from school. They are not allowed to return unless they have had a negative test or have isolated at home for 10 days, which also affects other members of their household. If they test positive, some schools send home so-called bubbles of children, which can include as many as 250 children.  

As many illnesses have symptoms that overlap with those of COVID-19, it is hard to distinguish the underlying cause. For example, symptoms indicative of influenza infection could be mistaken for COVID-19. With the influenza season approaching, it is likely that anyone displaying these symptoms will require a test to rule out COVID-19. Additional guidance is needed from health officials to help educate the public on when it is appropriate to get a test. 

With such uncertainty, it is understandable that there has been a huge surge in demand for tests. But the response by the UK Government is concerning. Many people have reported having to travel hundreds of miles to test centres because no tests or appointments have been offered locally. UK Health Secretary, Matt Hancock, has admitted that tests will be rationed, with some groups being granted priority access. It is difficult to believe that the Government did not predict the possibility of this increase in demand when children returned to schools and people went back to work. Dido Harding, head of NHS Test and Trace, claimed that the modelling used to advise the Government had not predicted such a steep increase in demand, and blamed SAGE for getting its predictions wrong. Nevertheless, demand for testing is up to 3 times higher than capacity—how has this scenario occurred? 

There does not seem to be a physical shortage of testing kits, more that they are not being distributed properly and it is difficult for people to get an appointment at one of the test centres. Also, laboratories processing the tests are limited in the number of tests they can do each day (375 000 tests per day) due to staffing and resources available. Although this number is much higher than back in March, Operation Moonshot, a Government pledge to reach 500 000 tests per day by the end of October, and 4 million by February next year, seems ambitious. 

Community testing is where the Government is falling short. According to a BBC report, nearly all community testing is processed in one of seven so-called Lighthouse Labs, which were close to capacity in August. Only one third of test results in community testing centres are returned within 24 h. If tests are not completed in a timely manner, results might not accurately reflect whether someone is infected. 

The situation can evolve rapidly, but it is not too late to prevent a repeat of earlier this year. Independent SAGE have released a 10-point emergency plan to avoid another national lockdown, to be implemented in this 2–3-week grace period before the situation worsens. They recommend a strategy to build a functional testing system: rebuild the testing system based on trusted local NHS and public health structures; recruit local contact tracers; provide clear, consistent, and culturally appropriate messaging about testing and effective measures; establish a clear strategy and set priorities for symptomatic and asymptomatic testing; and provide wrap around support, enabling people to self-isolate. 

Perhaps it is time to consider alternative methods of mass testing. Suggestions include using pooled saliva samples, which could allow for community testing at a lower financial cost. The COVID-19 symptom-tracker app from King's College London could also help track the spread of infection across the country. Testing should also be integrated through primary care to help triage patients in whom testing is necessary. 

Keeping the R number low is crucial to manage a second wave. But this number will be difficult to calculate, and inaccurate, without data on infection rates because of an inadequate testing system. Measures proposed by SAGE and Independent SAGE, if feasible, should be implemented as a matter of urgency. Otherwise the country could be forced into a lockdown by default.

What happens when COVID-19 collides with flu season?

Via JAMA: What Happens When COVID-19 Collides With Flu Season? Excerpt:

At a February 26 press conference, President Donald J. Trump said of the novel coronavirus, “This is like a flu,” and expressed surprise that as many as 69 000 people in the US die of influenza every year. 

However, the ensuing 5½ months have shown that coronavirus disease 2019 (COVID-19) is far deadlier and less predictable than seasonal influenza. Unlike influenza, COVID-19 does not appear to be seasonal, given the ever-increasing numbers of US cases this summer. 

So beginning this fall, the US for the first time will have to deal with a flu season wrapped in a global pandemic. Or, as the headline on a recent editorial by Edward Belongia, MD, and Michael Osterholm, PhD, MPH, described it, “a perfect storm.”  

Many questions remain about how flu season might affect the pandemic, and vice versa. For example, would coinfection with influenza worsen the course of COVID-19? Experts also aren’t certain whether influenza vaccination could help protect against COVID-19 or whether steps taken to mitigate COVID-19 will reduce the burden of the coming flu season.  

Some hints have come from preliminary research conducted in China, where influenza was still widely circulating when the first novel coronavirus infections emerged, and in the southern hemisphere, which is currently in the midst of its flu season.  

At least 2 things are clear: Quicker and more widely available testing is needed to distinguish between COVID-19 and influenza, which have similar symptoms, at least at first, but require different treatments. On top of that, a severe influenza season—the result of more virulent strains, inadequate vaccination rates, or a combination of both—coupled with a COVID-19 pandemic that shows no signs of abating, could overwhelm already taxed emergency departments and intensive care units.  

As pulmonary and critical care specialist Benjamin Singer, MD, wrote in a recent editorial, influenza and other causes of pneumonia represent the eighth leading cause of US deaths in nonpandemic years. 

“We can expect that the new reality of COVID-19 will only complicate the next influenza season,” Singer, of the Northwestern University Feinberg School of Medicine, concluded in his editorial.  

Flu-Like but Not Alike 

Distinguishing between influenza and COVID-19 “has important prognostic implications,” Singer said in an interview. “In many ways it matters that you find out quickly.” 

While the course of influenza is rapid, COVID-19 “kind of limps along a little bit,” he said. Knowing the reason for a patient’s respiratory symptoms “helps inform what you can expect.”  

Identifying the cause, of course, helps determine how best to treat respiratory symptoms, Singer noted. Although supportive care for influenza and COVID-19 is similar, drug treatments don’t overlap, he said. 

“We have things that we can do for COVID if we know someone’s infected,” he said. “If they have influenza, we can give antivirals targeted against influenza.” 

But mistakenly treating patients with influenza as though they have COVID-19 is wasteful and potentially harmful, Singer said.

What happens when flu meets Covid-19?

Via The Guardian: What happens when flu meets Covid-19? Excerpt:

Optimists had hoped Covid-19 might not withstand the blistering heat of a British summer. However those hopes have faded: the virus staged a recent resurgence in Iran amid actual blistering temperatures, and has had no trouble persisting in sultry Singapore. 

But what happens to Covid-19, and us, when the rain and chill – and flu and sniffles – of autumn set in? Especially, how will the annual winter flu epidemic play out amid a Covid-19 pandemic?  

One thing is a given. “We can expect waves of Covid in the fall,” says virologist Ab Osterhaus of the Research Centre for Emerging Infections and Zoonoses in Hanover. By then, he hopes, we might be better at treating severe cases, and more countries might be able to test, trace and quarantine all cases and their contacts, and contain the virus, better than they can now. 

The biggest worry in the UK is that hospitals can struggle to cope with the winter flu season. This year they will have to cope with Covid-19 as well, which shows no sign of going away by then, and could even surge if it turns out that cold temperatures, or the circulation of other autumn and winter viruses, boost its spread.  

The first problem will be figuring out which virus a patient has. Flu, Covid-19 and other seasonal respiratory diseases are virtually indistinguishable on the basis of symptoms, warns Barbara Rath of the University of Nottingham: even the loss of taste and smell many people get with Covid-19 is not unique. We need more and better diagnostic tests, she says, because the difference matters: medical staff need full protective gear to manage a Covid patient, but they can be vaccinated for flu. 

The real unknown is what Covid-19 does around other viruses. Every autumn there is a predictable series of outbreaks of respiratory viruses. It starts with rhinovirus, the main cause of the common cold, which breaks out every September as young children go to school and swap mucus. As no parent needs to be told, children are to sniffles what mosquitoes are to malaria. 

The rhinovirus subsides as most children are exposed and their immune systems activate. Then another virus breaks out: respiratory syncytial virus, or RSV. Every year in October or November, this causes mild colds in people of all ages, but sometimes severe lung infections in the youngest and oldest of us. RSV is so common that virtually all two-year-olds have already had it, and it sends more babies to hospital with pneumonia than any other virus.  

Then RSV subsides, and the annual flu epidemic sets in, anywhere from early winter to spring, driven mainly by transmission among children, but taking its main toll among the elderly: some 8,000 on average die yearly of flu in the UK. This predictable parade of infections almost seems a spiteful campaign by viruses to keep people, especially families with young kids, sick for as long as possible.  

But it is just a product of a little-understood phenomenon called “viral interference”: while one of these viruses holds sway in a person, or the population, for some reason the others can’t get a toehold. In September 2009, the swine flu pandemic that went on to sweep the world should have invaded Europe from the Americas. But the annual rhinovirus epidemic actually kept it at bay. The highly contagious new flu took over only when rhinovirus subsided, bumping RSV down the queue: RSV moved in only after that first wave of flu subsided. 

The question now is where Covid-19 is going to fit amid this viral jostling. Not every virus takes turns like this, says Ian MacKay of the University of Queensland. Sometimes you can be infected by two at once. So which kind is Covid-19?

'The virus doesn't care about excuses': US faces terrifying autumn as COVID-19 surges

Via The Guardian: 'The virus doesn't care about excuses': US faces terrifying autumn as Covid-19 surges. Excerpt:

In early June, the United States awoke from a months-long nightmare. 

Coronavirus had brutalized the north-east, with New York City alone recording more than 20,000 deaths, the bodies piling up in refrigerated trucks. Thousands sheltered at home. Rice, flour and toilet paper ran out. Millions of jobs disappeared. 

But then the national curve flattened, governors declared success and patrons returned to restaurants, bars and beaches. “We are winning the fight against the invisible enemy,” vice-president Mike Pence wrote in a 16 June op-ed, titled, “There isn’t a coronavirus ‘second wave’.” 

Except, in truth, the nightmare was not over – the country was not awake – and a new wave of cases was gathering with terrifying force. 

As Pence was writing, the virus was spreading across the American south and interior, finding thousands of untouched communities and infecting millions of new bodies. Except for the precipitous drop in New York cases, the curve was not flat at all. It was surging, in line with epidemiological predictions. 

Now, four months into the pandemic, with test results delayed, contact tracing scarce, protective equipment dwindling and emergency rooms once again filling, the United States finds itself in a fight for its life: swamped by partisanship, mistrustful of science, engulfed in mask wars and led by a president whose incompetence is rivaled only by his indifference to Americans’ suffering.  

With flu season on the horizon and Donald Trump demanding that millions of students return to school in the fall – not to mention a presidential election quickly approaching – the country appears at risk of being torn apart.  

“I feel like it’s March all over again,” said William Hanage, a professor of epidemiology at the Harvard TH Chan School of Public Health. “There is no way in which a large number of cases of disease, and indeed a large number of deaths, are going to be avoided.”  

The problem facing the United States is plain. New cases nationally are up a remarkable 50% over the last two weeks and the daily death toll is up 42% over the same period. Cases are on the rise in 40 out of 50 states, Washington DC and Puerto Rico. Last week America recorded more than 75,000 new cases daily – five times the rate of all Europe.  

“We are unfortunately seeing more higher daily case numbers than we’ve ever seen, even exceeding pre-lockdown times,” said Jennifer Nuzzo, an epidemiologist at the Johns Hopkins Center for Health Security. “The number of new cases that occur each day in the US are greater than we’ve yet experienced. So this is obviously a very worrisome direction that we’re headed in.”

The mayor of Houston, Texas, proposed a “two-week shutdown” last week after cases in the state climbed by tens of thousands. The governor of California reclosed restaurants, churches and bars, while the governors of Louisiana, Alabama and Montana made mask-wearing in public compulsory. 

“Today I am sounding the alarm,” Governor Kate Brown said. “We are at risk of Covid-19 getting out of control in Oregon.”  

As dire as the current position seems, the months ahead look even worse. The country anticipates hundred of thousands of hospitalizations, if the annual averages hold, during the upcoming flu season. Those hospitalizations will further strain the capacity of overstretched clinics.  

But a flu outbreak could also hamper the country’s ability to fight coronavirus in other ways. Because the two viruses have similar symptoms – fever, chills, diarrhea, fatigue – mistaken diagnoses could delay care for some patients until it’s too late, and make outbreaks harder to catch, one of the country’s top health officials has warned.

Willingness to vaccinate against COVID-19 in Australia

Via The Lancet Infectious Diseases: Willingness to vaccinate against COVID-19 in Australia.

More than half of the world's population faces long-term restrictions as the new normal to prevent the spread of COVID-19. If a vaccine becomes available, it might be possible to develop herd immunity and protect those who are most vulnerable to serious consequences of COVID-19. The population coverage required to achieve herd immunity through vaccination varies across diseases and is dependent on the basic reproduction number (R0). Modelling estimates R0 to be around 2·5 for severe acute respiratory syndrome coronavirus 2 when no restrictions or physical distancing measures are in place, and R0 reached almost 4·0 in Wuhan in early-mid January, 2020. Vaccination uptake for herd immunity would need to be at least 67% with an R0 of 3·0. In their Comment, the COCONEL Group reported that 26% of French adults would not accept a COVID-19 vaccine. We similarly explored this question among a diverse sample of Australian adults. 

We conducted an online survey of 4362 Australians aged 18 years and older during April 17–21, approximately 4 weeks after lockdown measures had been activated in Australia and at a time when potential deaths and health system capacity were still of great concern. We asked participants about actions or intentions toward the flu vaccine (“I have or I will get the flu vaccine this year”) and a potential COVID-19 vaccine (“If a COVID-19 vaccine becomes available, I will get it”).  

In this sample, 630 (14·4%) participants said they would not get the flu vaccine this year, 394 (9·0%) were indifferent, and 3338 (76·5%) said they have or will get the flu vaccine this year. For a COVID-19 vaccine, 213 (4·9%) said they would not get the vaccine, 408 (9·4%) were indifferent, and 3741 (85·8%) said they would get the vaccine if it became available. 

Individuals who said they would not get a COVID-19 vaccine were more likely to believe the threat of COVID-19 has been exaggerated (43·7% [93/213]) than those who said they would get the vaccine if it became available (11·5% [429/3741]) and those who were indifferent (19·9% [81/408]). Inadequate health literacy and lower education level were significantly associated with a reluctance to be vaccinated against both influenza and COVID-19 (p<0·001; appendix). Notably, a high proportion overall were confident in the state (75·4% [3288/4362]) and federal (65·2% [2845/4362]) government's response. 

In Australia, attitudes towards a COVID-19 vaccine appear to be more positive than reported in France in late March, which might in part reflect greater confidence in the government. However, our data show efforts are needed to target vaccine education to those with lower education and health literacy. 

It remains to be seen whether Australia's high intentions towards vaccine uptake will remain when restrictions are relaxed and the immediate perceived threat diminishes.