Adding To A Feverish Debate

Photo Credit –CDC PHIL

#6881

 

Long time readers may recall that during the summer of 2011 we looked at a study (see A Feverish Debate) that questioned the conventional wisdom of using antipyretic meds (ibuprofen, acetaminophen or paracetamol, etc) to reduce influenza-related fever.

 

This contrarian view made headlines when researchers from the Wellington based Medical Research Institute of New Zealand, published a paper (Antipyretic therapy for influenza infection—benefit or harm?) in the New Zealand Medical Journal.

 

You can read the entire paper, but their conclusion read:

 

We conclude that there is an insufficient evidence base to support the use of antipyretics in the treatment of fever from influenza infection.

 

The limited evidence that does exist suggests that the administration of antipyretics may have the potential to increase the severity of influenza illness and the risk of mortality.

 

We suggest that randomised controlled trials of the effect of antipyretics in the treatment of influenza are undertaken as an urgent priority.

 

We are still waiting for results from RCTs to support their concerns, but the idea of letting a fever run its course (at least, up to a point) as part of the body’s natural immune system’s defense isn’t new.

 

In a another story - also from 2011 - the American Academy of Pediatrics (AAP) released a report on the use of antipyretics in children, suggesting that we ought not over-treat fevers.

 

Clinical Report—Fever and Antipyretic Use in Children

Janice E. Sullivan, MD, Henry C. Farrar, MD,

ABSTRACT EXCERPTS

Fever in a child is one of the most common clinical symptoms managed by pediatricians and other health care providers and a frequent cause of parental concern. Many parents administer antipyretics even when there is minimal or no fever, because they are concerned that the child must maintain a “normal” temperature.

 

Fever, however, is not the primary illness but is a physiologic mechanism that has beneficial effects in fighting infection. There is no evidence that fever itself worsens the course of an illness or that it causes long-term neurologic complications.

(Continue . . . .)

 

 

Today, a study appears in the Journal of Pediatrics on another possible (albeit, rare) adverse effect seen in a small number of young children with fever and dehydration at a hospital in Indiana who received treatment with NSAIDs.

 

We’ve a press release from Indiana University that warns the administration of NSAIDs to reduce fever may result in AKI - Acute kidney Injury – in young children.

 

Common anti-fever medications pose kidney injury risk for children

Sick children, especially those with some dehydration from flu or other illnesses, risk significant kidney injury if given drugs such as ibuprofen and naproxen, Indiana University School of Medicine researchers said Friday.

 

In an article published online Jan. 25 by the Journal of Pediatrics, Jason Misurac, M.D., and colleagues from IU and Butler University reported that nearly 3 percent of cases of pediatric acute kidney injury over a decade could be traced directly to having taken the common nonsteroidal anti-inflammatory drugs, or NSAIDs.

 

Although relatively few in terms of percentage of total kidney damage cases, the children with problems associated with NSAIDs included four young patients who needed dialysis, and at least seven who may have suffered permanent kidney damage, the researchers said.

 

"These cases, including some in which patients' kidney function will need to be monitored for years, as well as the cost of treatment, are quite significant, especially when you consider that alternatives are available and acute kidney injury from NSAIDs is avoidable," Dr. Misurac, a fellow in pediatric nephrology, said.

 

Although such drugs have been linked to kidney damage in small, anecdotal reports, the study reported Thursday is believed to be the first large-scale study of the incidence and impact of acute kidney injury caused by NSAIDs.

 

The research team evaluated medical records at Riley Hospital for Children at IU Health in Indianapolis from January 1999 through June 2010 and found 1,015 cases in which patients had been treated for acute kidney injury from any cause.

 

After excluding cases in which the acute kidney injuries could possibly be explained by other factors, such as diseases affecting kidney function, the researchers found 27 cases, or 2.7 percent, in which the only factors were the administration of NSAIDs. In nearly all cases, the NSAIDs were administered before the children were admitted to the hospital. Because many of the 1,015 cases involved multiple potential causes of acute kidney injury, the researchers said the 27 cases are likely an underestimate of the number of cases in which NSAIDs contributed to the kidney damage.

 

Among the researchers' findings:

• Most of the children had been treated with recommended dosages.
• All of the children under the age of 5 needed to undergo dialysis temporarily, were more likely than the older children to be placed in an intensive care unit and needed longer hospital stays.
• The average cost for hospital and kidney specialist fees in the 27 cases was nearly $13,500, and the costs were much higher for younger children. At least $375,000 was spent on the NSAID-associated kidney injury cases at Riley Hospital over the study period, the researchers said, but billing data for other specialists were not available in the database, suggesting that the actual costs were likely much higher.

NSAIDs affect kidney function by restricting blood flow to the blood-filtering components of the kidneys, which suggests the risks from the drugs are greater among children who are dehydrated due to the effects of their illness, such as vomiting or diarrhea, Dr. Misurac said.

 

Fever is normal during an infection and not in itself dangerous, he noted, so "one alternative to NSAIDs would be acetaminophen, but another alternative would be no medication at all, at least for a while, to let the body fight the infection."

 

 

In a somewhat related story, I’ve written about studies that suggest that the concurrent use of antipyretics may inhibit the immune response when receiving vaccines.

 

In fact, it has even been theorized that one of the reasons that the elderly often develop less-than-robust immunity from the flu vaccine may be due to their frequent consumption of NSAIDs.

 

Several past blogs on this phenomenon include:

 

Anti-Inflammatory Meds And Vaccines

Common Pain Relievers May Dampen Vaccination Benefits

A Few Inflammatory Remarks

 

For now the evidence against the use of antipyretics (particularly NSAIDs) for fevers and influenza-like illness is very limited.

 

But these reports do show that - even after decades of use by hundreds of millions of people – our understanding of the effects of many commonly used over-the-counter medications remains less than complete.

A Feverish Debate

 

 

 

# 5687

 

Photo Credit –CDC PHIL

 

A topic I’ve written about several times in the past is back in the news again; the advisability of using antipyretic meds (ibuprofen, acetaminophen or paracetamol, etc) for flu-related fever.

 

The eye-catching headline and lede in yesterday’s New Zealand Herald reads:

 

'Don't use paracetamol for fever'

By Martin Johnston

5:30 AM Monday Jul 11, 2011

A respected scientific group has recommended not using paracetamol and several other drugs to reduce flu-related fever, saying they may increase the risk of death.

(Continue . . . )

 

 

The respected scientific group referenced in the article above is Wellington based Medical Research Institute of New Zealand. And their advice runs contrary to what we usually hear from our doctors, the CDC, and the World Health Organization.

 

Constant readers will recall that last May I wrote (see It Gives You Fever) about about a clinical trial this research group was about begin that would examine the merits and risks of taking antipyretics with influenza.

 

The concern is that when we take fever reducers, we lower the body’s temperature to provide symptomatic relief – but we also create a more favorable environment for the virus to replicate.

 

Essentially trading comfort for circumventing the body’s natural defense mechanism.

 

Last year, in A Hot Topic For Further Research I wrote about new research that suggested (but fell short of proving) that we may be better off carrying a bit of a fever – rather than reaching for the pill bottle -  when we have the flu.

 

And while that isn’t exactly a new idea, the evidence to support it has been limited.

 

The study – again conducted by the Medical Research Institute of New Zealand -  appeared in the Journal of the Royal Society of Medicine (registration required for access) – and provided a retrospective analysis of previous animal (not human) studies on the outcomes of the treatment of bacterial and viral infections with antipyretics.

 

The effect on mortality of antipyretics in the treatment of influenza infection: systematic review and meta-analysis

Sally Eyers, Mark Weatherall, Philippa Shirtcliffe, Kyle Perrin, and Richard Beasley

v.103(10); Oct 1, 2010

 

In a review of the existing literature, researchers at the Medical Research Institute of New Zealand and Capital & Coast District Health Board, identified 8 (non-human animal) studies that met their inclusion criteria.

 

They found that the risk of mortality increased by roughly 33% when antipyretics were used in influenza infected animals.  This risk was observed with aspirin, paracetamol, and diclofenac.

 

As I pointed out at the time, there were a lot of limitations to this study, not the least of which is that research on mice, chickens, and ferrets isn’t always applicable to humans.

 

Hence the need for the clinical trial on humans underway in New Zealand.

 

From the Medical Research Institute’s website, a description of goals of the clinical trial.

 

The effect on mortality of antipyretics in the treatment of influenza

Antipyretics are recommended for the symptomatic treatment of influenza infection.  However there is evidence that fever is a protective physiological response, that treating fever secondary to infections may be harmful and that human tropic influenza viruses are variable temperature-sensitive.

In a systematic review and meta-analysis we have identified that in animal models treatment with antipyretics for influenza infection increases the risk of mortality.  There are no randomised controlled placebo-controlled trials of antipyretic use in influenza infection in humans that reported data on mortality and a paucity of clinical data by which to assess their efficacy.

In response to these findings the MRINZ is now undertaking a placebo-controlled randomised trial of paracetamol use in influenza infection. This study is funded by the Health Research Council of New Zealand.

 

The results of that trial are not yet available, and so while the Medical Research Institute is publicly questioning the value of reducing fevers with influenza, they are not yet calling for health authorities to change their existing stance on the use of antipyretics.

 

They also state that using these meds as a pain reliever for muscle aches and headaches when you have influenza, is a reasonable practice.

 

And to round out this debate, the New Zealand Self Medication Industry Association (who have a vested interest in the sale of these products) has weighed in with the following press release.

 

Tuesday 12 July 2011, 12:13pm

Media release from New Zealand Self-Medication Industry Association

The New Zealand Self-Medication Industry Association (SMI), the industry body representing non-prescription consumer healthcare products, said today it was aware of a recommendation by the Wellington-based Medical Research Institute that antipyretics, such as paracetamol, ibuprofen and aspirin, not be used to reduce flu-related fever.

 

"We have only just received this information and, as the Institute itself said, there was insufficient evidence for the Ministry of Health to change its current position on these products. It's important people do not overreact and stop using antipyretics altogether.

 

Paracetamol and ibuprofen, for example, are well recognized for the relief of pain," commented SMI executive director Tim Roper.

"Fever management guidelines highlight that it is important to treat the patient and not the thermometer - SMI and its members endorse this approach. We are confident that if this approach is used, that these medicines can be used safely.

"Nevertheless, our members welcome the opportunity to work with Medsafe to discuss any matters that may arise, after the Ministry has reviewed the new information."

 

 

Although the jury is still out on all of this (and I’ve not discarded the Tylenol from my medicine cabinet), the American Academy of Pediatrics (AAP) released a report earlier this year on the use of antipyretics in children, suggesting that we ought not over-treat fevers.

 

Clinical Report—Fever and Antipyretic Use in Children

Janice E. Sullivan, MD, Henry C. Farrar, MD,

 

ABSTRACT EXCERPTS

 

Fever in a child is one of the most common clinical symptoms managed by pediatricians and other health care providers and a frequent cause of parental concern. Many parents administer antipyretics even when there is minimal or no fever, because they are concerned that the child must maintain a “normal” temperature.

 

Fever, however, is not the primary illness but is a physiologic mechanism that has beneficial effects in fighting infection. There is no evidence that fever itself worsens the course of an illness or that it causes long-term neurologic complications.

 

Thus, the primary goal of treating the febrile child should be to improve the child's overall comfort rather than focus on the normalization of body temperature.

 

(Continue . . . .)

 

 

And lastly, I would mention that in 2009 I wrote about some of the downsides to taking anti-inflammatory drugs like Aspirin, Tylenol, and Ibuprofen in a blog called  A Few Inflammatory Remarks.

 

It concerned a Lancet study that suggested giving babies acetaminophen (Tylenol) right before or immediately after getting a vaccination may inhibit or lower their immune response.

 

It also discussed several studies from the University of Rochester, that indicate the use of NSAIDs could lower the body’s antibody response.

 

It is axiomatic that there is no such thing as a 100% safe, 100% benign drug – even those you can buy over the counter.  

 

If there is a health benefit to be had, we must weigh that against the (usually very slight) risks of taking the these meds.

 

While the overall risks of taking these drugs are likely exceedingly small, hopefully we’ll soon have research that will help quantify the risks and rewards of using these common fever reducing medicines.

Study: Thermal Scanners & Pandemic Influenza

 

 

# 5538

 

 

A fresh study from the BMC Infectious Diseases journal on the efficacy of thermal scanners used to detect H1N1 influenza among arriving passengers at Japan’s Narita International Airport during the 2009 pandemic. 

 

As you are probably aware, many airports installed thermal scanners during the SARS outbreak of 2003 and during the pandemic of 2009, in an attempt to identify and interdict infected passengers upon arrival.

 

(Thermal Imaging in 2003)

Since fever is often a hallmark of infection, thermal imaging has been promoted as a way to protect the public and (hopefully) delay introduction of a virus into a country during a pandemic.

 

While all of this sounds reasonable, their usefulness has been the matter of considerable debate for years. 

 

The problem is, not everyone who is infected will exhibit a fever.

 

• Some may be silently incubating the virus, and will become symptomatic in another 24-48 hours
• Others may have other symptoms, but no fever
• Some may be taking antipyretics (fever reducers) to ease symptoms or evade detection
• And some may simply be asymptomatic carriers of the virus.

 

Added to these, scanners can be foiled by other factors including the consumption of hot beverages or alcohol, pregnancy, menstrual period or hormonal treatments.  All of which can increase the external skin temperature and cause a false positive.

 

Inversely, intense perspiration or heavy face make-up can have a cooling effect on the skin temperature which can cause a false negative.

 

In February of 2009, several months before the emergence of novel H1N1, I wrote about (LINK) a study that appeared in Eurosurveillance that listed these problems called:

 

International travels and fever screening during epidemics: a literature review on the effectiveness and potential use of non-contact infrared thermometers.

Euro Surveill. 2009;14(6):pii=19115.  

Bitar , A Goubar, J C Desenclos

 

In June of 2009, just as the pandemic was ramping up, I wrote  Vietnam Discovers Passengers Beating Thermal Scanners,  which looked at a Reuters report that a number of sick passengers flying into Ho Chi Minh City in Vietnam took fever reducers (Aspirin, Tylenol, etc) several hours prior to arrival in order to beat the thermal scanners.

 

In December of 2009, in Travel-Associated H1N1 Influenza in Singapore, I wrote about a NEJM Journal Watch of a new study that has been published, ahead of print, in the CDC’s  EID Journal  entitled:

 

Epidemiology of travel-associated pandemic (H1N1) 2009 infection in 116 patients, Singapore. Emerg Infect Dis 2010 Jan; [e-pub ahead of print]. Mukherjee P et al

Travel-Associated H1N1 Influenza in Singapore

Airport thermal scanners detected only 12% of travel-associated flu cases; many travelers boarded flights despite symptoms.

Travelers play a key role in spreading many infections, including influenza. Such was the case with the spread of 2009 H1N1 influenza to Singapore, a major travel hub serving 37 million air passengers annually.

<SNIP>

One quarter of patients were symptomatic when they boarded flights; 15% developed symptoms during travel. Airport thermal scanners detected only 12% of patients overall and only 40% of those with symptomatic infection on arrival.

 

And finally, last June CIDRAP carried this piece on a presentation at last year’s ICEID.

 

Thermal scanners are poor flu predictors

Thermal scanners for screening travelers do moderately well at detecting fever, but do a poor job at flagging influenza, according to researchers from New Zealand who presented their findings today at the International Conference on Emerging Infectious Diseases (ICEID) in Atlanta.

They assessed the performance of the machines from Aug 21 through Sep 12, 2008, on 1,275 passengers arriving from Australia at Christchurch International Airport. The investigators took the travelers' tympanic temperatures and obtained respiratory samples for influenza testing from 1,268 of them.

The positive predictive value for fever was 1.5% for thermal scanners and 4.1% for tympanic thermometers. For influenza, the positive predictive value for the two techniques was 2.8%. None of the 30 passengers who tested positive for influenza had a tympanic temperature of 37.8°C (100°F) or higher, and only 2 had temperatures of at least 37.5°C (99.5°F). Three were asymptomatic. The group concluded that fever is a poor predictor of influenza, which limits the efficacy of thermal screening at entry points.
Jul 13 ICEID abstracts (See Board 168)

 

 

These older less-than-encouraging findings all serve as prelude to today’s study, which finds similar limitations with the use of thermal scanners to detect influenza during a pandemic.

 

Detection rates of H1N1 were found to be just over 22% and thermal imaging sensitivity for detecting fevers ranged from just over 50% to just under 70%.

 

 

I’ve only reproduced the abstract. Follow the link to read this open access study in its entirety.

 

Fever screening during the influenza (H1N1-2009) pandemic at Narita International Airport, Japan

Hiroshi Nishiura  and Kazuko Kamiya

BMC Infectious Diseases 2011, 11:111doi:10.1186/1471-2334-11-111

Published:3 May 2011

Abstract (provisional)

Background

Entry screening tends to start with a search for febrile international passengers, and infrared thermoscanners have been employed for fever screening in Japan. We aimed to retrospectively assess the feasibility of detecting influenza cases based on fever screening as a sole measure.

Methods

Two datasets were collected at Narita International Airport during the 2009 pandemic. The first contained confirmed influenza cases (n=16) whose diagnosis took place at the airport during the early stages of the pandemic, and the second contained a selected and suspected fraction of passengers (self-reported or detected by an infrared thermoscanner; n=1,049) screened from September 2009 to January 2010. The sensitivity of fever (38.0 C) for detecting H1N1-2009 was estimated, and the diagnostic performances of the infrared thermoscanners in detecting hyperthermia at cut-off levels of 37.5 C, 38.0 C and 38.5 C were also estimated.

Results

The sensitivity of fever for detecting H1N1-2009 cases upon arrival was estimated to be 22.2% (95% confidence interval: 0, 55.6) among nine confirmed H1N1-2009 cases, and 55.6% of the H1N1-2009 cases were under antipyretic medications upon arrival. The sensitivity and specificity of the infrared thermoscanners in detecting hyperthermia ranged from 50.8-70.4% and 63.6-81.7%, respectively. The positive predictive value appeared to be as low as 37.3-68.0%.

Conclusions

The sensitivity of entry screening is a product of the sensitivity of fever for detecting influenza cases and the sensitivity of the infrared thermoscanners in detecting fever. Given the additional presence of confounding factors and unrestricted medications among passengers, reliance on fever alone is unlikely to be feasible as an entry screening measure.

 

 

Despite the aggressive use of thermal imagers, passenger interviews, and other screening methods - Japan found it impossible to prevent entry of the H1N1 virus into their country during the early days of the 2009 pandemic.

 

In Japan: Quarantine At Ports Ineffective Against Pandemic Flu  I wrote about a study that suggests between asymptomatic or mild infections, and a silent incubation period of several days, there wasn’t much chance of long-term success.

 

For every person identified, and quarantined, by port authorities  - researchers estimate 14 others infected by the virus entered undetected.

 

First a article from The Yomiuri Shimbun, followed by a link to the study which appears in Eurosurveillance.

 

Quarantine at ports found ineffective against new flu

The Yomiuri Shimbun

The number of people infected with new flu who passed undetected through airport quarantine between April last year, when the new strain of influenza began spreading, and May was about 14 times higher than the number of infected people stopped at the airports, according to a study carried out by Tokyo University.

Eurosurveillance, Volume 15, Issue 1, 07 January 2010

Rapid communications

When should we intervene to control the 2009 influenza A(H1N1) pandemic?

H Sato , H Nakada, R Yamaguchi, S Imoto, S Miyano, M Kami

 

Politically, and in terms of reassuring the public, the deployment of thermal scanners at airports and other points of entry probably has a lot of merit.   And they can provide valuable surveillance information as well.

 

Practically, as an effective way to keep an emerging virus out of a country, these studies continue to show how unlikely that outcome really is.

It Gives You Fever

 

 

# 5534

 

 

Photo Credit – PHIL

 

An interesting study is about to get underway in New Zealand which will look at the potential downside to taking antipyretics – fever reducers – when you have influenza.

 

When we take antipyretics, we lower the body’s temperature to provide symptomatic relief – but we also create a more favorable environment for the virus to replicate.

 

Last year, in A Hot Topic For Further Research I wrote:

 

Today we have some new research that suggests (but falls far short of proving) that we may be better off carrying a bit of a fever – rather than reaching for the pill bottle -  when we have the flu.

 

And while that isn’t exactly a new idea, the evidence to support it has been limited.

 

It makes sense, of course.

 

A fever is the body’s way of combating an infection.  And we know human adapted flu viruses replicate in a narrow temperature range, and that replication is inhibited by fever.

 

If we reduce the fever, we are (theoretically, anyway) undermining our body’s own protective immune response.

 

And that in turn could increase the amount of time we remain ill, and shed the flu virus.

 

First the study in the Journal of the Royal Society of Medicine (registration required for access) – which is a retrospective analysis of previous animal (not human) studies on the outcomes of the treatment of bacterial and viral infections with antipyretics.

 

The effect on mortality of antipyretics in the treatment of influenza infection: systematic review and meta-analysis

Sally Eyers, Mark Weatherall, Philippa Shirtcliffe, Kyle Perrin, and Richard Beasley

v.103(10); Oct 1, 2010

In a review of the existing literature, researchers at the Medical Research Institute of New Zealand and Capital & Coast District Health Board, identified 8 (non-human animal) studies that met their inclusion criteria.

 

They found that the risk of mortality increased by roughly 33% when antipyretics were used in influenza infected animals.  This risk was observed with aspirin, paracetamol, and diclofenac.

 

 

This retrospective study was on animals, not humans, and so the question remains; Is it desirable to carry a low fever when battling influenza?

 

Over the next few months a clinical trial at special ward at Wellington Hospital in New Zealand may help answer that question. It will be used to monitor the progress of 80 influenza patients who will receive either paracetamol (acetaminophen) or a placebo for fever.

 

The story from Stuff.nz.co, then I’ll return with a bit more.

 

 

Flu study kicks off clinical trials unit

KATE NEWTON

A new clinical trials unit at Wellington Hospital will let researchers carry out studies that have not been possible in New Zealand before.

 

The first trial will be to study if giving paracetamol to people with influenza makes it worse.

 

The 14-bed unit is the first in a New Zealand public hospital.

 

It will let researchers keep participants in medical studies overnight for close monitoring – significantly widening the scope of what trials can be done.

(Continue . . .)

 

 

In a somewhat related story, I’ve written about studies that suggest that the concurrent use of antipyretics may inhibit the immune response when receiving vaccines.

 

In fact, it has even been theorized that one of the reasons that the elderly often develop less-than-robust immunity from the flu vaccine may be due to their frequent consumption of NSAIDs.

 

Several past blogs on this phenomenon include:

 

Anti-Inflammatory Meds And Vaccines

Common Pain Relievers May Dampen Vaccination Benefits

A Few Inflammatory Remarks

 

For now the evidence against the human use of antipyretics (and NSAIDs) in these situations is faint (at best).

 

But these reports do show that the effects of many over-the-counter medicines – even those used for decades by hundreds of millions of people - remain incompletely understood.

A Hot Topic For Further Research

 

 

 

# 5055

 

 

Look into just about any modern medicine cabinet and you are likely to find the workhorse of over-the-counter medications – antipyretics; fever reducers, that also reduce pain and/or inflammation.

 

Aspirin, paracetamol (acetaminophen), and ibuprofen are often the first (and sometimes only) medicine we reach for when we have the flu.  

 

Today we have some new research that suggests (but falls far short of proving) that we may be better off carrying a bit of a fever – rather than reaching for the pill bottle -  when we have the flu. 

 

And while that isn’t exactly a new idea, the evidence to support it has been limited.

 

It makes sense, of course.  

 

A fever is the body’s way of combating an infection.  And we know human adapted flu viruses replicate in a narrow temperature range, and that replication is inhibited by fever.

 

If we reduce the fever, we are (theoretically, anyway) undermining our body’s own protective immune response. 

 

And that in turn could increase the amount of time we remain ill, and shed the flu virus.

 

First the study in the Journal of the Royal Society of Medicine (registration required for access) – which is a retrospective analysis of previous animal (not human) studies on the outcomes of the treatment of bacterial and viral infections with antipyretics.

 

 

The effect on mortality of antipyretics in the treatment of influenza infection: systematic review and meta-analysis

Sally Eyers, Mark Weatherall, Philippa Shirtcliffe, Kyle Perrin, and Richard Beasley

v.103(10); Oct 1, 2010

In a review of the existing literature, researchers at the Medical Research Institute of New Zealand and Capital & Coast District Health Board, identified 8 (non-human animal) studies that met their inclusion criteria.

 

They found that the risk of mortality increased by roughly 33% when antipyretics were used in influenza infected animals.  This risk was observed with aspirin, paracetamol, and diclofenac.

Abstract (Excerpt)

Conclusion

In animal models, treatment with antipyretics for influenza infection increases the risk of mortality. There are no randomized placebo-controlled trials of antipyretic use in influenza infection in humans that reported data on mortality and a paucity of clinical data by which to assess their efficacy. We suggest that randomized placebo-controlled trials of antipyretic use in human influenza infection are urgently required, and that these are sufficiently powered to investigate a potential effect on mortality.

 

 

There were a lot of limitations to this study, not the least of which is that research on mice, chickens, and ferrets isn’t always applicable to humans.

 

Particularly since mice (used in many of these studies) can exhibit a fall in body temperature when infected with the influenza virus (Behavioral thermoregulation in mice inoculated with influenza virus), which could skew some of these results.

 

But these findings certainly do invite further study, particularly considering how often use of antipyretics are recommended in the treatment of influenza.

 

In a somewhat related story, over the past couple of years I’ve written about studies that suggest the administration of antipyretics may inhibit the immune response from vaccines.

 

In fact, it has even been theorized that one of the reasons that the elderly often develop less-than-robust immunity from the flu vaccine may be due to their frequent consumption of NSAIDs.

 

Several past blogs on this phenomenon include:

 

Anti-Inflammatory Meds And Vaccines

Common Pain Relievers May Dampen Vaccination Benefits

A Few Inflammatory Remarks

 

 

None of this is offered as medical advice, of course.  For that, I would refer you to your healthcare provider and to the recommendations of your public health departments. 

 

For now, the evidence against the human use of antipyretics (and NSAIDs) in these situations is faint (at best). And so I’m not about to weed out my medicine cabinet over this.  

 

Not yet, anyway.

 

But these reports do illustrate that the complex physiological effects of many over-the-counter medicines – even those used for decades by hundreds of millions of people - remain incompletely understood.

 

A little humility-inspiring lack of certitude with which to start your week.