Airborne Precautions

Article Author:
Binish Ather
Article Editor:
Peter Edemekong
5/23/2020 9:37:51 AM
PubMed Link:
Airborne Precautions


An airborne disorder is any disease that is caused by a microorganism that is transmitted through the air. There are many airborne diseases that are of clinical importance and include bacteria, viruses, and fungi. These organisms may be spread through sneezing, coughing spraying of liquids, the spread of dust or any activity that results in the generation of aerosolized particles. It is important to be aware that airborne diseases, in general, do not include disorders caused by air pollution such as poisons, smog, and dust.[1][2]

The microorganisms transmitted airborne may be spread via fine mist, dust, aerosols, or liquids. The aerosolized particles may be generated from a source of infection such as body secretions of an infected patient or even an animal. In addition, aerosols may be generated from biological waste products that accumulate in garbage, caves and dry arid containers. During aerosolization, the microorganisms that are less than 5 microns in size float in the air. Sometimes, the microorganisms may be contained in dust particles that are present in the air. Once the droplets that contains microorganisms have been formed, they are then dispersed via air currents to varying distances and can be inhaled by susceptible hosts.[3][4][5][4]

The infected aerosolized particles often remain suspended in the air currents and may travel considerable distances, although many particles will drop off within the vicinity. As the distance traveled of the aerosol particle increases, the risk of infection starts to drop. Airborne precautions necessitate the prevention of infections and use of available interventions in healthcare facilities to prevent the transmission of airborne particles. The airborne particles often remain suspended in the facility air environment and with air currents move along to different parts of the institution where there is a potential of them being inhaled by other patients. The airborne particles may remain localized to the room or move depending on the airflow. In some cases where there is inadequate ventilation, the airborne particle may remain in the hospital room and be inhaled by a newly admitted patient.

The control and prevention of airborne transmission of infections are not simple as it requires the control of airflow with the use of specially designed ventilator systems, the practice of antiseptic techniques, wearing personalized protection equipment (PPE) and performing basic infection prevention measures like hand washing.[6][7][8]

Airborne Organisms

In almost all cases, airborne pathogens cause an inflammatory reaction of the upper airways affecting the nose, sinuses, throat, and lungs. The involvement of these structures may result in nasal or sinus congestion, and sore throat. Any coughing or sneezing activity may then generate aerosolized particles. Some of the common infections that can spread via airborne transmission include the following:

  • Anthrax (inhalation)
  • Chickenpox
  • Influenza
  • Measles
  • Smallpox
  • Cryptococcosis
  • Tuberculosis

Airborne disease is not exclusive to humans but can also affect non-humans. For example, many types of poultry are often affected by an avian disorder (Newcastle disease), that is also transmitted via an airborne route. However, it is important to understand that exposure to an animal or a patient with an airborne disease does not automatically ensure disease transmission. The infection also depends on the host immunity, how much exposure the individual has suffered and the duration of exposure to the infected patient.[5][9][10][11]

Airborne Particles Generated from Medical Equipment

Besides patients, there are also several medical and surgical procedures that can generate aerosolized particles. In most cases, these airborne particles are generated during manipulation of the large airways. Examples include:

  • Manual ventilation with a bag and mask
  • Intubation
  • Open endotracheal suctioning
  • Bronchoscopy
  • Cardiopulmonary resuscitation
  • Sputum induction
  • Surgery on the lungs
  • Nebulizer therapy
  • Non-invasive positive pressure ventilation (BIPAP, CPAP)
  • An autopsy on the lungs


Factors that influence airborne transmission[3][6][7][11][8][11][7][6][3]

Airborne transmission of microorganisms depends on several physical variables endemic to the infectious particle. Factors that influence the spread of airborne infections includes the following:

  • Temperature
  • Humidity
  • Rainfall
  • Amount of sunshine
  • Wind
  • Human behavior
  • Tropical storms hurricanes, monsoons, or typhoons

Other Factors

  • These factors affect the distance of spread, duration, and infectiousness of droplet particles. For example, the influenza virus is relatively easily spread in the northern hemisphere because of climate conditions that favor infectiousness of the virus but many bacterial infections cannot spread outdoors for most of the year, and thus remain in a state of dormancy.
  • The ultraviolet (UV) rays of the sun are harmful to both bacteria and viruses. The strength and duration of UV light exposure can determine the survival of infectious pathogens; In those parts of the country with a higher average of daily sunshine and those close to the equator, some pathogens lose their infectious ability.
  • However, if the levels of humidity are high, then even in the presence of UV light, the infectious particle can survive for a longer period. It is believed that this is due to the formation of vapor around the aerosolized particles which acts as a barrier to the UV rays.
  • Several studies have shown that after tropical storms, the first quantity of fungal spores is diminished but within a few days, the number of spores will increase exponentially compared to normal environmental conditions.
  • Socioeconomic and living conditions: Like infectious diseases that are spread via contact, the role of living conditions and socioeconomic factors plays a key role in airborne transmission. Dwelling and the number of people residing in one area is an important aspect. The spread of disease is much faster in urban areas compared to rural areas. In urban areas, buildings and other high-rise structures make transmission of bacterial and viral pathogens relatively easy, but in rural areas, airborne particles containing fungal spores are more common.
  • Residing near a source of water such as a lake or river can also be a cause of airborne disease outbreaks, especially after a change in the local watershed.
  • In poor countries, inadequate sewage and drainage systems also increases the risk of formation of airborne particles and spread. Working with certain animals also increases the risk of spread of certain airborne diseases.
  • The indoor environment also affects the spread of airborne diseases. The indoor ventilation, use of air conditioning and humidity all affect the rate of spread of infectious airborne pathogens.
  • Inadequate ventilation has been implicated in the airborne transmission of several respiratory viruses.
  • Poor or inadequate ventilation has been implicated in several airborne infections such as Legionella pneumophila. Poor maintenance of air conditioning systems can lead to water stagnation and spread of aerosolized particles.

Issues of Concern

Management Principles

When patients are seen in the emergency room or admitted to the hospital, it is impossible to know immediately if there have an airborne infection. [12][13] Hence, healthcare workers need to maintain a high degree of suspicion in patients who present with signs and symptoms that are compatible with an airborne infection. The earlier the airborne prevention methods are implemented, the lower the risk to other patients and staff.[11][14]

Airborne Isolation Room

This is a single patient room equipped with special air handling (negative pressure) and ventilation capacity. The negative pressure room is also known as an Airborne Isolation Room. This negative pressure room is usually a single-occupancy patient-care room frequently used to isolated individuals with confirmed or suspected airborne infection.[15][16][17]

Elements of an Airborne Isolation Room [5][11][8]

  • Negative pressure ventilation that creates inward directional airflow from corners of the room
  • The airborne isolation room should have a toilet and sink for the patient, and a designated hand washing sink for healthcare workers.
  • Have monitoring equipment including alarms.
  • Transmit exhaust of air from the hospital room to the outside of the building
  • Recirculate air through a HEPA filter before being returned to the general circulation
  • The door to the room must be kept closed to maintain negative pressure even if the patient is not in the room.
  • The windows in the room should remain closed at all times; opening the window may cause the reversal of airflow, which counters the benefits of a negative pressure room.
  • All healthcare providers who enter the isolated negative pressure room must be fit tested for an N95 respirator.
  • Only healthcare providers immunized to the organism in question should enter a room where airborne precautions are in place for varicella or measles or varicella. A respirator is not necessary for immunized individuals but is required for non-immunized workers who provide care.
  • The negative pressure room should have dedicated personal hygiene facilities including a toilet and bathing facilities.
  • One should also have a point of care evaluation for every patient interaction so that one can determine the need for additional precautions.

What is an Anteroom? [16][8]

This is relatively clean and is a frequently used area to transition patients/healthcare workers in and out of the airborne isolation room when it is under negative pressure. An anteroom is frequently used as a transitional space between the airborne isolation room and the hallway. It is in this transition area where healthcare workers store their PPE and put on their PPE before entering the airborne isolation room.

  1. The laundry hamper is usually located inside the patient room.
  2. The sink is usually in the anteroom location.
  3. The only items that are stored in the anteroom are the procedure or surgical masks, N95 respirator, eye protection devices, gloves, and gowns.
  4. At the hand washing sink, an alcohol-based hand sanitizer and disinfectant wipes should be available.
  5. Posters showing how to perform hand washing must be placed at the sink.

Clinical Significance

Personal Protective Equipment (PPE)[5][11][16]

All healthcare workers who enter the negative pressure room should wear an appropriately fit-tested N95 respirator. The N95 Respirators is individually fitted and can filter particles one micron in size. Studies show that the mask has a 95% filter efficiency and provides a tight facial seal with less than a 10% leak.

To use the  respirator appropriately, one should do the following:

  • Hand hygiene should be performed before putting on a respirator.
  • Perform a seal check
  • To avoid self-contamination after use, remove the respirator using the straps. Avoid touching any part the part which may have microorganisms on it.
  • When the respirator is not in use, it should not be dangled in front of the neck or top of the head.
  • If the respirator becomes soiled, wet or is splashed with body fluids, it should be promptly removed.
  • After use, the respirator should be removed, and one should thoroughly wash hands.
  • The N95 respirator must be fit tested for all healthcare workers assigned to treat the particular patient.
  • All N95 respirators must be cited by OSHA and have an efficiency rating.

Patient Movements

In hospitals, patients admitted to the negative room often have to be transported to other departments like radiology, physical therapy, the pulmonary laboratory or even another hospital. Before sending a patient with an airborne infection, one must always communicate with the relevant department first. This communication should include the following:

  • Patient diagnosis
  • What type of precautions are necessary?
  • Name of physician
  • What type of restriction is required?
  • What is the duration of restriction?
  • Who can transport the patient?


  • Other than transporting the patient to another department, unless it is medically necessary, the patient should be restricted to his or her room.
  • During transport, the patient should wear a surgical mask
  • There may be situations when during the transport the patient may not be able to wear a mask. In such scenarios, the transport should be performed in a way to limit the exposure to other patients or staff. This means the transport staff should not wait in the reception area or leave the patient in a holding area.
  • The patient should preferably be transported in an empty elevator, and the personnel that is transporting the patient should be told to maintain infectious disease precautions throughout the transportation.
  • If the patient is intubated, call respiratory therapist ahead of time to ensure that the transport is done according to respiratory guidelines.
  • Finally, the transport personnel should wear an N95 respirator depending on their immune status.

Patient and Family Education

  • Education of the patient and or family is necessary to ensure that they adhere to the preventive guidelines.
  • The patient and family should be educated on coughing etiquette to ensure the minimum spread of the aerosolized particles.
  • Tissue should be placed over the nose and mouth, which should be disposed of in the appropriate waste container.
  • This should be followed by appropriate hand hygiene.

Patient Visitors

  • A sign should be placed outside the door recommending infectious precautions.
  • All visitor must adhere to the precautions as stated on the front door.
  • The nurse must assess the health risk of each visitor before they enter the room.
  • The nurse must instruct all visitors to wash hands.
  • The patient, family and all visitors must be educated on washing hands and contact precautions.
  • The number of visitors should be limited.
  • All visitors should be educated about the potential risk of acquiring an infection and should be asked to wear an N95 respirator.
  • Young children, elderly and others who are ill from chronic illness should be told not to enter the room.

Duration of Precautions

In general, airborne precautions can be discontinued once the patient shows no signs or symptoms of an infection.[16][18][19][8] However, one also has to be aware of the period of incubation and if unsure, always consult with an infectious disease expert

  1. Anthrax: Individuals exposed to aerosolized B anthracis spores must at least 8 weeks of antimicrobial therapy. This is a serious infection with very high mortality if the diagnosis is missed. An infectious disease consult should be involved in the management of patients with anthrax. The patient usually remains infectious while symptoms remain. In any case, because this is a potential agent for terrorism, it is important to seek advice from the CDC. Patient isolation is mandatory, and all traffic must be curtailed.
  2. Chickenpox: Most patients remain infectious for 5 to 7 days after the rash develops. By this time most of the vesicles have dried up, and the risk of transmission is low.
  3. Influenza: Patients with influenza may remain infectious even before they have symptoms. In most cases, the viral shedding occurs at the time of the symptoms and will continue for 5 to 10 days. Data indicate that younger children and infants may shed the virus for a week or two, thus placing other individuals at risk for acquiring the infection. In patients who are immunocompromised, the shedding may last for 4-12 weeks.
  4. Measles (aka rubeola) is the most contagious infectious diseases, with a secondary infection rate in susceptible domestic contacts over 90 percent. The majority of patients remain contagious from 1 to 2 days before the onset of symptoms. Younger patients may remain contagious 4 to 5 days before and after the rash. Immunocompromised individuals remain contagious throughout the duration of the illness.
  5. Smallpox is not a concern in many parts of the world, but it is a contagious infection. However, unlike measles, influenza, and pertussis, the transmission rate is low. Once smallpox is acquired, the patient remains contagious from the onset of the fever and rash. The highest viral shedding occurs during the first 2 weeks of the rash. Infection rates of anywhere from 40% to 80% have been reported.
  6. Cryptococcosis is being seen more often now because of transplantation. However, in healthy people, the risk of acquiring or developing an infection is very low. However, all immunocompromised individuals remain at high risk for acquiring Cryptococcus. An infectious disease consult is necessary to determine the period of isolation.
  7. Tuberculosis is a common disease, but it is not as contagious as measles or influenza. Even when acquired, only 5% of individual will develop clinical disease. The risk of disease transmission is most common in close living quarters. Data reveal that about 20% of household contacts do develop a positive skin test to PPD. Small epidemics have been reported in closed environments like that in an airplane. Populations at high risk for infection include health care workers and nursing home residents. The patient usually remains infectious while symptoms are present, which can be a few weeks.

What if there are many infected patients?

  1. When there is an isolated case of suspected airborne infection, the individual would be kept in a single room with negative pressure ventilation. However, what if there is a large breakout of an airborne infection which has affected many patients? In such cases, one should contact the infectious disease expert to determine where and how these patients should be isolated.
  2. If the facility doesn't have a properly ventilated room, the patient should be transferred to a facility with such accommodations. Arrangements for transfer should be coordinated between the two institutions so that a minimum never of people are involved during the transfer. If a single room is not available, there should be a physical separation of the patient from others.

Managing Deceased Patients

When a patient is deceased, airborne precautions are necessary when handling and preparing the body during transfer to the morgue and an autopsy.

Managing specimens and rooms of patients and with airborne infections

  1. Once a patient with an infectious disorder like measles, tuberculosis or varicella has been discharged, it is important to continue airborne precautions and decontaminate the room.
  2. Upon discharge or discontinuation of airborne precautions, the door must remain closed and negative air flow maintained until all air in the room has been recirculated/placed. This process usually requires 45 to 60 minutes.
  3. Masks, face shields, and goggles help protect the mucous membrane of the eyes, mouth, and nose from exposure to the patient's excretions and aerosols. These devices should be used when performing any procedure which can result in the generation of air sprays such as during suctioning. A mask should only be used once, and when it is wet or soiled, it should be changed/ All reusable equipment must be disinfected before being used again
  4. Soiled linen: the role of soiled linen in disease transmission is negligible, but still housekeeping should use common sense hygienic practices when handling linen. Soiled linen should be handled with gloves and away from the body with minimal agitation to prevent dispersion of microorganisms into the air. The laundry hamper should be close to the location so that the linen can be placed inside rather than carry it a long distance. If there is obvious contamination with body fluids, the linen should be placed in a plastic bag, and laundry personally should be told to wear gloves, also an apron when handling the linen.
  5. Proper handling and transport of specimens: All body specimens should be considered to be infectious and handled safely. The specimen container should be properly closed and clean on the outside. All requisition should be free of body fluid. The specimen container must be placed in a sealed plastic bag.
  6. When performing an invasive procedure on an infected patient, one should away use an aseptic technique that prevents the transfer of microorganisms from the patient to the healthcare staff. Aseptic techniques include:
  • Hand washing with an alcohol-based hand sanitizer
  • Opening surgery instrument sets and supplies only when they are ready to be used
  • Preparing the patient's skin with an antiseptic like chlorhexidine
  • Covering the patient with an appropriately sized sterile drape to prevent transferring microorganisms from the patient’s skin or the environment to the exposed areas during the procedure
  • Use of single-use clean gloves or sterile gloves, sterile gown, mask, as indicated by the specific procedure being performed
  • Maintaining a sterile field during the procedure

Other Issues


Ways to prevent airborne diseases include the following:

  • Washing hands
  • Appropriate hand disinfection
  • Regular immunizations against diseases believed to be locally present
  • Wearing a respirator
  • Limiting time spent around any patient likely to be a source of infection.
  • Having a negative pressure isolation room

Enhancing Healthcare Team Outcomes

The management of airborne infections is with an interprofessional team aided by hospital guidelines and rules. All healthcare workers including the nurse have a vital role in preventing airborne infections. an interprofessional team approach involving clinicians and nurses will produce the best results in preventing the spread of infections. The following principles should apply:

  1. Mostly, antibiotics or antiviral drugs are not usually prescribed to prevent or control infections caused by viruses. However, antibiotics may be prescribed to a patient with the flu, to control or prevent secondary bacterial infections.
  2. Recommendations from the CDC for the public include maintaining careful hygiene and sanitation protocols and getting vaccinated against the organisms associated with airborne infections.
  3. If the number of negative pressure rooms is limited, set priority for use. For example, infectious tuberculosis is the highest booty followed by measles, then variceal then disseminated zoster and finally extensive localized zoster.
  4. In an emergency situation, when there is no airborne isolation room, at least, pull the privacy curtains and require all personnel to wear an N95 respirator. Ask visitors and other patients to leave the area.
  5. One may also use UV air purification devices that are EPR certified and FDA approved to inactivate a wide range of airborne infectious disorders.
  6. It is important that all health care workers be aware of their immune status. Individuals who have problems with immunity or have not been vaccinated should not be allowed to take care of patients with vaccine preventive airborne infections like chicken pox or measles.


[1] Gammon J,Hunt J, A review of isolation practices and procedures in healthcare settings. British journal of nursing (Mark Allen Publishing). 2018 Feb 8     [PubMed PMID: 29412028]
[2] Broussard IM,Bhimji SS, Precautions, Universal null. 2018 Jan     [PubMed PMID: 29262198]
[3] Brouqui P,Boudjema S,Soto Aladro A,Chabrière E,Florea O,Nguyen H,Dufour JC, New Approaches to Prevent Healthcare-Associated Infection. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 2017 Aug 15     [PubMed PMID: 28859352]
[4] MacIntyre CR,Chughtai AA,Rahman B,Peng Y,Zhang Y,Seale H,Wang X,Wang Q, The efficacy of medical masks and respirators against respiratory infection in healthcare workers. Influenza and other respiratory viruses. 2017 Nov     [PubMed PMID: 28799710]
[5] Moriceau G,Gagneux-Brunon A,Gagnaire J,Mariat C,Lucht F,Berthelot P,Botelho-Nevers E, Preventing healthcare-associated infections: Residents and attending physicians need better training in advanced isolation precautions. Medecine et maladies infectieuses. 2016 Feb     [PubMed PMID: 26654322]
[6] Baseer MA,Ansari SH,AlShamrani SS,Alakras AR,Mahrous R,Alenazi AM, Awareness of droplet and airborne isolation precautions among dental health professionals during the outbreak of corona virus infection in Riyadh city, Saudi Arabia. Journal of clinical and experimental dentistry. 2016 Oct     [PubMed PMID: 27703605]
[7] Ito Y,Nagao M,Iinuma Y,Matsumura Y,Yamamoto M,Takakura S,Igawa J,Yamanaka H,Hashimoto A,Hirai T,Niimi A,Ichiyama S,Mishima M, Risk factors for nosocomial tuberculosis transmission among health care workers. American journal of infection control. 2016 May 1     [PubMed PMID: 26777287]
[8] Lindsley WG,Noti JD,Blachere FM,Szalajda JV,Beezhold DH, Efficacy of face shields against cough aerosol droplets from a cough simulator. Journal of occupational and environmental hygiene. 2014     [PubMed PMID: 24467190]
[9] Beam E,Gibbs SG,Hewlett AL,Iwen PC,Nuss SL,Smith PW, Clinical challenges in isolation care. The American journal of nursing. 2015 Apr     [PubMed PMID: 25811520]
[10] Seto WH, Airborne transmission and precautions: facts and myths. The Journal of hospital infection. 2015 Apr     [PubMed PMID: 25578684]
[11] Paton R,Tolhurst N,Perisa M,Dempsey K,Tallon J, What mask to use? Australian nursing     [PubMed PMID: 29235820]
[12] Peterson K,Novak D,Stradtman L,Wilson D,Couzens L, Hospital respiratory protection practices in 6 U.S. states: a public health evaluation study. American journal of infection control. 2015 Jan     [PubMed PMID: 25564126]
[13] Katz LM,Tobian AA, Ebola virus disease, transmission risk to laboratory personnel, and pretransfusion testing. Transfusion. 2014 Dec     [PubMed PMID: 25403825]
[14] Tajima K,Nishimura H,Hongo S,Hazawa M,Saotome-Nakamura AI,Tomiyama K,Obara C,Kato T, Estimation of secondary measles transmission from a healthcare worker in a hospital setting. International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases. 2014 Jul     [PubMed PMID: 24780918]
[15] Patrick MR,Hicks RW, Implementing AORN recommended practices for prevention of transmissible infections. AORN journal. 2013 Dec     [PubMed PMID: 24266933]
[16] Hines L,Rees E,Pavelchak N, Respiratory protection policies and practices among the health care workforce exposed to influenza in New York State: evaluating emergency preparedness for the next pandemic. American journal of infection control. 2014 Mar     [PubMed PMID: 24457143]
[17] Seto WH,Conly JM,Pessoa-Silva CL,Malik M,Eremin S, Infection prevention and control measures for acute respiratory infections in healthcare settings: an update. Eastern Mediterranean health journal = La revue de sante de la Mediterranee orientale = al-Majallah al-sihhiyah li-sharq al-mutawassit. 2013     [PubMed PMID: 23888794]
[18] Benson SM,Novak DA,Ogg MJ, Proper use of surgical n95 respirators and surgical masks in the OR. AORN journal. 2013 Apr     [PubMed PMID: 23531312]
[19] Silkaitis C,Bardowski L,Coomer C,Trakas K,Lavin MA,Reddy S,Bolon MK,Zembower TR, Use of acid-fast bacilli staining to determine the need for airborne infection isolation precautions: a comparison of respiratory specimens. American journal of infection control. 2014 Nov     [PubMed PMID: 25248484]