Questions raised about study on masks as aerosol barrier

first_imgFeb 28, 2007 (CIDRAP News) – A recent study has raised expectations that simple surgical masks might offer a reasonably good substitute for N-95 respirators for healthcare workers seeking protection from airborne viruses, but others say the study is seriously flawed.In the study, Y. Li and associates, from Hong Kong Polytechnic University, measured how much of a potassium chloride spray penetrated masks and respirators worn by people walking on a treadmill. They found that the surgical masks filtered out at least 95% of the material, while the N-95 respirators filtered out 97%.This suggested that “surgical masks and N-95 respirators can provide effective protection in a relatively low viral loading environment,” says the report, published in the December 2006 issue of the American Journal of Industrial Medicine. Such a finding, if true, could be a blessing for healthcare facilities during an influenza pandemic, since masks are less costly than respirators and likely to be in better (though still limited) supply.The Li study drew more attention when it was described in a Feb. 15 report by the Clinicians’ Biosecurity Network, part of the Center for Biosecurity at the University of Pittsburgh Medical Center (UPMC). In that report, Erick Toner, MD, of UPMC wrote, “The current study, supported by the clinical observations from the SARS epidemic, provides evidence that a surgical mask may provide significant protection from aerosols as well as droplets.”While affirming that N-95s should be used in high-risk settings, Toner wrote that if N-95s are not available, “use of a surgical mask along with other routine barriers (gown, gloves, and goggles) may afford significant protection from infection, especially in low risk settings.”However, experts at 3M Co. in St. Paul, which makes both surgical masks and N-95 filtering facepiece respirators, told CIDRAP News the Li study has serious methodologic defects that undermine its conclusions. The researchers did not assess the size of the particles used or employ an accepted method for counting the particles sprayed onto the mask and the particles that penetrated it, among other problems, the 3M experts said.Questions also were raised by Raymond Tellier, MD, a University of Toronto microbiologist who says he is not an expert on aerosols but who has monitored and written about research on the risk of airborne transmission of flu viruses. Tellier said the Hong Kong researchers did not appear to use methods consistent with those recommended by the US National Institute of Occupational Safety and Health (NIOSH).Surgical masks are designed mainly to protect other people from respiratory droplets or particles expelled by those wearing the masks, whereas N-95 respirators are designed to reduce the wearer’s exposure to potentially harmful particles in the surrounding air. N-95 filtering facepiece respirators are designed to be sealed against the face to limit exposure to airborne particles, and manufacturers recommend testing the fit. Surgical masks, in contrast, typically allow significant air leakage around the edges.Whether healthcare workers should use masks or respirators to protect themselves from flu viruses has been increasingly debated in the face of the threat of a pandemic. Scientific evidence is unclear on how long flu viruses can remain in the air after being expelled in a cough or sneeze, though the traditional view has been that they usually come in relatively large droplets that quickly fall to the ground. Surgical masks are not designed to protect wearers from airborne particles.Until last fall, the US Department of Health and Human Services’s (HHS’s) pandemic flu plan recommended that healthcare workers wear surgical masks during routine care of pandemic flu patients. But in view of the uncertainty about airborne transmission of flu, in October HHS issued new guidelines saying that N-95 respirator use is “prudent” for medical workers caring for pandemic flu patients.Meanwhile, a committee of the Institute of Medicine of the National Academy of Sciences is currently examining evidence about masks, respirators, and other personal protective equipment for medical workers. The committee is expected to issue a report next September, an IOM official told CIDRAP News last week.Hong Kong study protocolThe Hong Kong researchers used 10 volunteers to test the filtration effectiveness of an N-95 respirator made by 3M and a surgical mask made by Winner Medical Group of Hong Kong. In a series of tests, each volunteer wore a mask or a respirator while a solution containing potassium chloride and a fluorescent stain (Fluorescein) was sprayed at them from an atomizer 1 meter away. The tests were conducted with the volunteers at rest and walking on a treadmill at three different speeds.The amount of material that penetrated the masks was measured in two ways. The researchers separated the used masks and respirators into layers, placed the layers in water, filtered out the fibers, and determined the weight of the potassium residue in the water. The results showed that 0.56 mg of potassium reached the innermost layer of the respirators, versus 0.79 mg of potassium for the surgical masks.In the second measurement, the volunteers’ faces were photographed, and the photos were used to assess the amount of Fluorescein stain on their faces, using a 7-point scale. The researchers said this qualitative test confirmed that the respirators were more efficient filters.”The in-vivo filtration tests show that both N-95 respirators and surgical masks have 95% or greater filtration efficiency, and N-95 respirators have about 2% filtration efficiency higher than surgical masks,” indicating that both can provide protection in “a relatively low viral-loading environment,” the investigators wrote.But they added, “It is important to note that 3-5% of the solution can still penetrate both types of masks, which may become critical when the viral loading is high.” They also cautioned that they tested only one brand of respirator and one brand of mask, and the findings are limited to those types.Methodologic weaknesses citedSpecialists at 3M evaluated the Hong Kong study at CIDRAP’s request. “Overall, what was done by Li et al is not considered filtration efficiency testing and should not be used to evaluate filtration efficiency or compare media. They also did not use accepted methods for evaluating the fit to the face which is a very important component in reducing exposure to airborne particles,” said Robert Weber, lab manager for technical service and regulatory affairs in 3M’s Occupational Health and Environmental Safety division.A key problem with the study is that the researchers didn’t determine the size of particles that were generated by the atomizer they used, said Craig Colton, a 3M senior technical service specialist. “Filtration is very dependent on particle size, so if you’re talking about efficiencies you need to know about particle size,” Colton said in an interview. “Without that critical piece of information, it’s hard to know what you’re comparing.””We know they used a nebulizer, but we don’t know what particle size that nebulizer was designed to produce,” he added. “Oftentimes they produce different particle sizes depending on the conditions under which they operate. Changing concentrations of different salts can change the particle size formed. They assumed they were testing in the most penetrating particle size range. This is not a safe assumption to make.”The Li study says that potassium chloride was used instead of sodium chloride as the test aerosol because NIOSH has said that potassium chloride content in human sweat is very low, which implies a reduced chance of confounding the results. But Colton said the standard NIOSH approach calls for sodium chloride.He said the study also should have included a control group of volunteers wearing the masks and doing the same exercises but not being sprayed with the test solution. That would have made it possible to exclude the chance that potassium chloride from other sources, such as the volunteers’ sweat or the masks themselves, would affect the results.The use of a fluorescent stain to test the mask and respirator was also questioned by 3M. Weber commented via e-mail, “The use of scanning subjects with fluorescent light to determine the effectiveness of filtration is not a proven method to determine either filtration efficiency or fit. This method is not quantitative and does not take into account particles that do not settle onto the face (those that are deposited in the lung and those that remain airborne). This method only demonstrates that particles are entering the mask, most likely due to significant faceseal leaks.”Colton said the fluorescent stain method has never been calibrated to determine what degree of particle penetration is associated with what degree of staining.The report by Li and colleagues says that the volunteers “followed the manufacturer’s instructions including the pressure tightness test” when donning the N-95 respirator. However, Weber of 3M said in his e-mail, “Fit testing was not done prior to the testing to determine if the wearers had a good fit and would be qualified to wear the N-95 respirator.”A 2006 study published in the Journal of Hospital Infection exemplified a more accepted method of testing the effectiveness of respiratory protection, according to Colton. In that study, investigators from the Chinese University of Hong Kong used commercially available instruments to count the particles inside and outside three different types of protective equipment worn by volunteers: surgical masks, “laser masks” (special masks used during laser surgery), and a respirator called an FFP2, similar to an N-95. A particle generator was used to produce sodium chloride particles of a known size range. The researchers found that the respirator provided significantly better protection than either type of surgical mask, though the laser mask was marginally better than the other mask.Toronto microbiologist raises questionsTellier, a microbiologist at Toronto’s Hospital for Sick Children and associate professor at the University of Toronto, also raised questions about the methods of Li and colleagues, though he took pains to point out that he is not an expert on filter testing. Tellier wrote an article in Emerging Infectious Diseases last year urging US and Canadian health agencies to strengthen their recommendations on respiratory protection for medical workers in a flu pandemic.Commenting by e-mail, Tellier said the NIOSH test method for respiratory protection calls for using sodium chloride particles in a particular size range and an airflow rate of 85 liters per minute, because the difference between respirators and surgical masks diminishes at lower airflow rates. It’s not clear whether Li and colleagues used that prescribed flow rate, he said.Tellier also suggested that the masks in the Li study were hit by droplets, not solid particles, which would change the results. Spraying a potassium chloride solution from 1 meter away produces droplets of liquid “in the aerosol [size] range,” but “if they remain liquid until they hit the mask, what we are measuring . . . is the penetration of the mask by an aqueous solution, which can be repelled in part by waterproofing and the remaining liquid would adsorb into the fabric; the latter would not occur with ‘solid’ particles.”My understanding is that testing with solid particles is more in keeping with aerosol protection and this is what NIOSH recommends,” Tellier stated.See also:Li Y, Wong T, Chung J, et al. In vivo protective performance of N-95 respirator and surgical facemask. Am J Ind Med 2006 Dec;49(12):1056-65 [Abstract]Derrick JL, Li PTY, Tang SPY, et al. Protecting staff against airborne viral particles: in vivo efficiency of laser masks. J Hos Infect 2006 Nov;64(3):278-81Oct 18, 2006, CIDRAP News story “HHS backs respirator use in caring for pandemic flu patients”Sep 29, 2006, story “Airborne flu viruses threaten health workers, expert says”last_img read more

The Indianapolis 500

first_img“When I was a kid, every single day during May you heard something about the Indianapolis 500 no matter where you lived in Indiana.  This year I guess they are having a 500 on May 24, but you wouldn’t know it unless you lived in Indianapolis.  I have seen no hype anywhere–exception is the Indy Star.  You would think that for the 99th running of this race you would at least hear about it on the myriad of sports shows available on TV.  I have heard nothing.It would be nice to know who is considered the top driver this year, what kind of speeds they are running, when all the events are taking place, etc.  Do you remember when nearly a half million people would witness this race live?  All the month of May you could listen to Donald Davidson on the radio talking about the 500.  Names like Foyt and Andretti were household names.  Jim Nabors will not even be there this year!How many of you know these names?  Castroneves, Carpenter, Rahal, Hunter-Ray.  There is a good chance one of these drivers could win this race.  It is no longer the “Greatest Spectacle in Racing”.last_img read more

Kenya’s COVID-19 cases hit 31,441 after 426 test positive

first_img426 people have tested positive for COVID-19 out of 5,158 samples collected in the last 24 hours Health CAS Mercy Mwangangi has said. This now brings the country case load to 31,441 number of positive cases.From the cases all are Kenyans except nine who are foreigners with 239 males and 187 females.Also Read  Uhuru extends curfew ahead of his address Tuesday next week Cumulative tests in the country now stands at 407, 610.Cases by Counties is as follows; Nairobi 132, Kajiado 63, Kericho 48, Kiambu 24, Machakos 21, Migori 17, Mombasa 16, Kitui 13, Laikipia 13, Nakuru 11, Kisumu 11, Uasin Gishu 10, Tharaka Nithi 8, Nyeri 7, Busia 7.Also Read  Govt moves to resolve land allocation dispute in East MauMore Counties: Makueni 6, Kilifi 4, Garissa 3, Nyandarua 3, Isiolo 2, Embu 2, Meru 1, Kirinyaga 1, Kakamega 1, Baringo 1, and Lamu 1.Also Read  Relief for families as MOH revises Covid-19 burial protocols257 patients have recovered from the disease, with 195 being from the Home-Based Care program and 62 from various hospitals. Total number of recoveries now stand at 17,869.She revealed that the COVID-19 death toll had risen to 516 after 10 more patients died from complications related to the highly contagious respiratory disease. Speaking during the daily COVID-19 briefing, Dr. Mwangangi confirmed the youngest case is a three-month old infant while the oldest is 88 years.Get breaking news on your Mobile as-it-happens. SMS ‘NEWS’ to 20153last_img read more

MoUs should be shared with public – former Minister

first_imgAmid some public outcry and concerns raised to have Memorandums of Understanding (MoU) signed between the Government of Guyana and other countries released to the general public, former Foreign Trade Minister, Dr Henry Jeffrey feels the Government should do so.Dr Jeffrey feels there is nothing secretive in MoUs that cannot be shared, especially since it is not a legally binding document and does not tie one Government to the other to deliver on any specific area, unless a contract is signed.“On the other hand, you could have MoUs that are narrow and those that are broad to deal with a general context of Guyana and to deal with any specific issue. But why shouldn’t they be made public? I don’t see them as any kind of documentation that could not be,” he stated during an interview with <<<>>>> on Wednesday.The former Minister advised that Government consult with stakeholders to determine whether or not there is anything that they may want to include. He said this may help in a large way to put some of the concerns they may have, to rest. Most importantly though, he said it allows for information sharing between Government and the citizenry.Only recently, Opposition Leader Bharrat Jagdeo had called for Government to release the oil MoU signed between Guyana and Trinidad and Tobago.Concerns in this regard were also raised by the local Private Sector, particularly the Georgetown Chamber of Commerce and Industry (GCCI) where it said individuals and business people here are fearful that the MoUs will give foreigners a greater advantage.In fact, before the signing of the energy-related MoU with neighbouring Trinidad and Tobago (T&T), President of GCCI, Deodat Indar called for Government to show constraint where the oil industry is concerned and also made the call for the signing to be placed on hold, while assessing the impact such a move would have on local businesses.The GCCI head claimed Guyanese businesses are already being sidestepped, and instead contracts have been awarded to foreign-based companies to benefit from the local oil sector. The Chamber was mainly concerned with the Guyana Government selling out opportunities to foreigners as opposed to locals.Jeffrey said, “Let’s understand this clearly. Every country has to look after its interest but a MoU can’t sell you out, it’s for the Government of Guyana to make it public and involve people in it construction so that they may bring different points of view on the issues. But I don’t believe a MoU will sell anybody out. I think the issue lies in the fact that Guyanese were not treated well by Guyana.”In July, Guyana and China signed a MoU on cooperation within the framework of Beijing’s global “Belt and Road Initiative,” which represents yet another milestone in Guyana-China relations. The accord is expected to enhance cooperation in five main areas; namely policy coordination, facilities connectivity, trade and investment, financial integration, and people-to-people interaction. Public infrastructure is also expected to be a major focus under this agreement.At the completion of the signing, there were also calls for that MoU to be released. While the Government released the MoU signed with T&T, Minister of State Joseph Harmon said the issue will be first discussed at Cabinet before a decision is made.And in an effort to boost local capacity in the oil and gas sector, the Governments of Guyana and Canada’s Newfoundland will also sign a MoU this month.Canadian High Commissioner to Guyana, Lillian Chatterjee says the Natural Resources Minister from the Canadian Province of Newfoundland will be visiting Guyana tomorrow to ink the agreement.The Canadian envoy said the MoU will last for three years and will allow Guyana the opportunity of learning how Newfoundland managed to utilise that sector to improve its economy.Canada has the third largest oil reserves, is the fifth largest oil producer and fourth largest oil exporter in the world.last_img read more

DD TRAVEL: CHECK OUT AMAZING OFFERS TO SALOU WITH ATLANTIC TRAVEL

first_imgCambrils ParkYes, it’s Monday morning and yes, it’s raining cats and dogs across Donegal.Why not cheer yourself up and check out Salou and the fantastic Cambrills Park?Atlantic Travel are offering fantastic value in Cambrils Park, Salou, starting at €459 per bungalow for selected dates in May 2017, The Aloha Bungalows sleep up to 6 people. May 08th €459 – 2017May 22nd €578 – 2017May 29th €714 – 2017Cambrils Park is an immaculately presented campsite, ideal for a fun-filled family holiday. The roads are lined with palm trees and pampas grass, and emplacements are located near the first-class facilities, of which the lagoon-style pool complex is undoubtedly the focal point. 

Soak up the atmosphere on the grassy terrace, or enjoy a cooling short swim across to the bar in the centre of the pool, while the children have fun on the small water slides. There is also a second pool complex on site, popular with young children for its dragon water slide and life-sized elephants that squirt water. In the evening sample a delicious Spanish speciality or tasty pizza from the on-site restaurant, and follow that with some lively family-orientated entertainment.www.atlantictravel.ie074 9126193 SalouThe town of Salou is a favourite destination with Irish tourists; it’s located on the Costa Dorada, or ‘the Gold Coast’, in the Catalonia region of Spain. It is the most visited of the holiday resorts on the Costa Dorada, with a clean, sandy coastline, which stretches far into the horizon. Salou is just 20 minutes from Reus Airport.

Salou has become one of the main tourist areas of Costa Dorada, with over two million visitors a year attracted to its hot, golden Mediterranean beaches. Salou has become a popular family resort with its safe shallow waters, friendly locals, Port Aventura theme park and a great variety of entertainment facilities and attractions.

Culture
Salou, like many other Mediterranean towns, has a rich cultural history. While it doesn’t portray as strong a cultural heritage as the neighbouring towns of Tarragona and Reus, Salou has its own subtleties. 

The modern buildings built as tourism expanded in the town blend with the classical styled older buildings. The Church of Santa María del Mar was built in 1766, consisting of a church with a walled belfry and single bell, it was mainly used by seafaring folk. It was extended early in the 20th century to its present form.

Beaches
The popularity of Salou as a holiday resort is largely built on its superb beaches. The coastline of Salou enjoys eight main beaches, each with fine golden sand and inviting shallow waters due to the long beach and slow tide.

The beaches themselves are quite varied, some beaches consisting of long plains of sand, some mixing with the beachfront hotels and bars, while others have coved areas sheltered with pine trees giving a more intimate feel.

The Ponent Beach joins with neighbouring resort Cambrils, while Llevant beach, the largest in Salou, has specially designated areas in the summer for sporting activities.

Capellans Beach is quite small but a very attractive open beach, while Llenguadets and Llarga beaches are littered with small coves and are shielded by pine trees.

Penya-Tallada, Cala de la Font and Cala Crancs beaches are all quite small but have a very tranquil atmosphere.

Shopping
Keen shoppers will be spoilt for choice in Salou; the local shopkeepers pride themselves on providing a good friendly service. While Salou as a whole has many shopping zones, the Old Town area contains some shops, which are as old as Salou has been a holiday resort. 

The Jaume I Promenade and Major Street areas are more modern shopping areas, containing many restaurants and terrace cafes underneath a canopy of palm trees.

Market day
The weekly market here is a good chance to see what traditional Salou has to offer. The Municipal Market area also contains many solid, year-round businesses including food shops, fashion boutiques and restaurants.

Leisure & recreation
Salou has many activities for both children and grown ups. Port Aventura theme park, owned by Universal, is a fantastic modern theme park built around the basis of five worlds, with rides to match the theme of each world. The park also has 25 live shows a day as well as restaurants and bars.

Salou also has two water parks – Aquaopolis and Aqualeon. While both are filled with the slides and pools you would expect from a waterpark, Aqualeon also has a zoo with a large selection of animals.

Many hotels and bars in Salou will provide entertainment throughout the day and night for both adults and children, while the beaches play host to many sporting activities and water sports, the surrounding streets provide play parks and terrace cafes, and at night a selection of clubs and bars light the pavements.

Bikes are available for hire in Salou. Horse riding is available nearby. The coast here is excellent for sea fishing. The many paths make this a great place for walkers and runners alike. Golf is available nearby.

Eating out
Local restaurants in Salou serve mainly Catalan dishes, many of which are based on fresh fish caught in the local clear waters, but also incorporates many traditional Spanish dishes such as paella. Plenty of restaurants and hotels in Salou will serve traditional foods alongside the more international tasting fast-foods such as burgers, pizzas and hot dogs.

Cuisine
A coastal town, Salou favours seafood in its local gastronomy; there are some excellent bars and restaurants in the town and along the coast where you can enjoy the delicious catch of the day. 

Romesco Sauce made with olive oil, hazlenuts, almonds sweet peppers, onions, garlic and tomatoes, is a local speciality; its mainly served with fish, but is also delicious accompanying meat dishes. 

Other specialities of the region include Arrs Negre – rice boiled in cuttlefish ink, Rossejat – a rice or noodle dish made with fish broth and calamars amb xocolata, or chocolate squid. Tarragona is renowned for its white wine production; look out for the Tarragona wine denomination when selecting a wine to accompany your meal. 

Climate
Salou enjoys mild winters with some rainfall, warm blossom filled springs long hot summers and autumns of golden sunlight and rich sweet plums.DD TRAVEL: CHECK OUT AMAZING OFFERS TO SALOU WITH ATLANTIC TRAVEL was last modified: June 27th, 2016 by StephenShare this:Click to share on Facebook (Opens in new window)Click to share on Twitter (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to share on Reddit (Opens in new window)Click to share on Pocket (Opens in new window)Click to share on Telegram (Opens in new window)Click to share on WhatsApp (Opens in new window)Click to share on Skype (Opens in new window)Click to print (Opens in new window)last_img read more