There are reported cases that people have been infected twice by the virus. Nevertheless, at some stage population-based serological testing may help to determine the proportion of people who have immunity to SARS-CoV-2 which will help the authorities to relax the social distancing restrictions. Moreover, this information will provide if the population develops “Herd immunity” i.e. High level of immunity in the population which will stop the virus circulating in the community. This is how the natural flattening of epidemiological graph occurs.
PUBLIC HEALTH MEASURES WHICH PREVENT SPREAD OF COVID-19
Public health Prevention measures of pandemic spread of COVID-19 may be designed in different levels and methods depends on the local situation.
1. Travel warnings and restrictions
Travel warnings start from Level 1 (Practice usual precaution), Level 2 (Practice enhanced precautions) and Level 3 (Avoid non-essential travel) when there is widespread transmission.
In addition to the travel warnings the government may impose post-travel mandatory quarantine and prohibition of non-citizens from entry. In unprecedented escalation of transmission in the community mainly from international or interstate travel, the borders may be closed.
2. Community containment strategies
Surveillance is the main activity in any country in controlling the disease transmission. This includes case finding (Prompt detection of infected cases) and contact tracing (Detection of contacts who were exposed to persons who are infected). When maximizing early detection of cases, it is important that the testing suspected cases based on symptoms, sites or areas of high risk of infection, and local transmission status.
Isolation refers to the separation of ill persons with COVID-19 infection and quarantine is the separation or restriction of activities of persons who are believed to have been exposed to the infection. This may be either self-home isolation (Voluntary) or mandatory isolation in dedicated facilities. In Australia mandatory quarantine came into effect for inbound passengers.
Social distancing is another important aspect of public measure in controlling human tohuman transmission. These interventions range from measures to increase social distance among community members (e.g., cancellation of public gatherings, use of masks, implementation of community-wide “snow days”) to community-wide quarantine. At the community level this may be implemented to entire community or region, with focus measures such as restriction of non-essential travel/ visit whilst keeping essential services and certain shops open, whilst practicing social distancing all the time.
Sometimes the government imposes widespread community quarantine including cordon sanitaire (Sanitary barrier) with curfews.
Generally, Graded Implementation of Community Containment Measures are necessary in different levels based on ground situation.
WHAT CAN YOU DO TO PREVENT SPREAD OF COVID-19?
Transmission of any organisms from person to person via respiratory secretions (From nose & throat). Mode of transmission is important to understand to use the appropriate preventive measures.
1. Aerosol transmission
In normal breathing or talking a person generate respiratory aerosols as they are small size particles suspend in the air for a longer period. Some organisms such as tuberculosis (TB), measles and chickenpox transmit via aerosols.
2. Droplet / Contact transmission
Droplets are larger particles (Generally size > 5-10 µm and produced by normal breathing, coughing or sneezing. While normal breathing the droplets travel up to 2m (Distance of social distancing distance). However, coughing and sneezing may propel droplets up to 6m (That’s why cough etiquette is important) As they are larger particles and heavy they fall on the surface / floor. Any direct contact with the nasal / oral secretions may also spread the organisms in the persons hands and may be contaminated in other body areas or objects. Therefore, virus may be found in the surfaces, objects, floor, clothes and even body surfaces from generated droplets or touching contaminated areas (Indirect contact)
SARS CoV-2 transmits from person to person either direct or indirect contact as the virus is found in the respiratory secretions (Mucus from nose & mouth) and predominantly transmitted via droplets. There may be some viruses found in aerosols, however a very tiny amount of virus may also spread through aerosols, but the viral concentration is generally not adequate to produce clinical infection. However, aerosol transmission is likely particularly healthcare workers work close proximity in relatively enclosed space for extended period of time (Creates high viral concentration). For this reason, healthcare workers treating patients with symptoms suggesting of COVID-19 or confirmed cases, wear medical mask. There is some evidence the virus may go through the stomach and spread through faeco-oral route as well.
In public setting, the main precaution of SARS-CoV-2 transmission is based on droplets and contact preventions. As droplets generally travel up to 2m, social distancing is the most important preventive measure. General public is unlikely contract the virus airborne unless they are unable to avoid crowds and many symptomatic people. Surgical mask is designed to protect droplets (Larger particles) and not aerosols. Therefore, it is not recommended for general public to use surgical mask unless they have any respiratory symptoms, in this situation the mask can prevent him/her spreading the virus to others.
In healthcare setting, the healthcare workers generally use surgical masks (one mask per patient) when they encounter a patient with respiratory symptoms. However, if a healthcare provider works in a highly contaminated area or treating patients with COVID-19, they should wear N-95 respirator to protect aerosol transmission.
Generally wearing gloves in public settings not necessary as they do not prevent transmission. Regular hand sanitation is more effective. Gloves may carry germs and in fact enhance viral transmission unless you change gloves all the time. In healthcare setting, gloves can prevent transmission when healthcare provider get in contact with the patients with symptoms. The gloves are changed for every patient contact.
Wash your hands often with soap and water for at least 20 seconds especially after you have been in a public place, or after blowing your nose, coughing, or sneezing, going to the bathroom; and before eating or preparing food.
If soap and water are not readily available, use a hand sanitizer that contains at least 60% alcohol. Cover all surfaces of your hands and rub them together until they feel dry.
Avoid touching your eyes, nose, and mouth with unwashed hands. o Avoid close contact with people who are sick
Cover your mouth and nose with a tissue when you cough or sneeze or use the inside of your elbow.
Throw used tissues in the trash.
➢ Do not share: You should not share dishes, drinking glasses, cups, eating utensils, towels, or bedding with other people or pets in your home.
Cleaning around house – What do you need to know?
(1) High risk Situation
Household member with COVID-19 positive or
Household member is in social isolation (Direct contact with positive case or suspect case waiting for COVID-19 test results)
(2) Moderate risk situation
Household member healthcare worker / returning home after visiting high risk areas e.g visiting medical facility
Household member is vulnerable E.g. Elderly > 70 years, People with chronic disease such as diabetes or who is on immunosuppressive treatment.
(3) Low risk situation
People who are house-bound who does not have visitors coming into the house and no vulnerable members in the house
Usual everyday cleaning (Mechanical cleaning)
Use a detergent such as everyday cleaning product (E.g. Spray and wipe) or soap and water to clean high-touched areas.
Cleaning & Disinfecting
First clean the surface with a detergent or soap and water or usual household detergent (E.g Spray & wipe) to remove the dirt, which will make the virus easier to remove. Following this use a disinfectant to kill the virus. Only necessary if a surface has been contaminated with infectious material. The choice of cleaning product will be based on the type of surface you are cleaning and how likely it is that it is contaminated by the COVID-19 virus. If you feel the risk of contamination is high, you may like to opt for a stronger bleachbased solution for the disinfecting part of the process. Wipes can be used to clean surfaces, however, unless the product is a disinfectant that kills viruses, you may need to use a disinfectant product after you clean.
Tips for effective cleaning against coronavirus
Use a clean cloth or disposable paper towel.
Cleaning: Pay special attention to the bathroom and toilet, as well as frequently touched surfaces such as tables, countertops, light switches, doorknobs and cabinet handles, and personal items such as mobile phones.
Disinfecting: Be sure to follow the instructions on products or they could be ineffective. Be careful not to mix different cleaning products, as this can create dangerous solutions. For the disinfectant to be as effective as possible, make sure it has contact with the surface for at least 5–10 minutes to kill bacteria and viruses.
Dispose of gloves and cleaning cloth (or wash thoroughly) and wash your hands thoroughly with soap and water.
You do not need to be obsessive in frequent cleaning and disinfecting if you are not in high risk situation. Once a day through cleaning of high-touched surfaces are suffix.
And airdry for at least 10 minutes
➢ Disinfecting clothes
Disinfect laundry basket with disinfectant as outlined above. Use laundry detergent with contains bleach (If appropriate to the clotehs) Choose warmest available water setting (Usually 60 -90°C) (SARS CoV-2 is sensitive to heat at 70°C)
➢ Disinfecting shoes
This may only be necessary for those who work in high risk environment/ highly infected area.
Remove your shoes & socks in the garage or entrance or keep them in plastic bags The shoes may be disinfected with a disinfectant wipe.
Masks to symptomatic individuals
If you are sick: You should wear a facemask when you are around other people (e.g., sharing a room or vehicle) and before you enter a healthcare provider’s office. If you are not able to wear a facemask (for example, because it causes trouble breathing), then you should do your best to cover your coughs and sneezes, and people who are caring for you should wear a facemask if they enter your room.
If you are NOT sick: You do not need to wear a facemask unless you are caring for someone who is sick (and they are not able to wear a facemask). Facemasks may be in short supply and they should be saved for caregivers.
Monitor symptoms of healthy individuals
Seek medical care and call ahead to your Doctor if you have symptoms of a fever, cough, shortness of breath, pain or pressure in your chest, confusion, bluish lips or face
Isolation & treatment of infected
If you are sick with COVID-19 or suspect you are infected with the virus that causes COVID-19, follow the steps below to help prevent the disease from spreading to your co-workers, family or others:
Myths & Facts about Wearing facial masks & gloves
Stay at home until instructed to leave: Patients with confirmed COVID-19 should remain under home isolation precautions until the risk of secondary transmission to others is thought to be low.
Talk to your healthcare provider: The decision to discontinue home isolation precautions should be made on a case-by-case basis, in consultation with healthcare providers and state and local health departments.
Stay away from others: As much as possible, you should stay in a specific room and away from other people in your home. Also, you should use a separate bathroom, if available.
Limit contact with pets & animals: You should restrict contact with pets and other animals while you are sick with COVID-19, just like you would around other people. Although there have not been reports of pets or other animals becoming sick with COVID-19, it is still recommended that people sick with COVID-19 limit contact with animals until more information is known about the virus.
When possible, have another member of your household care for your animals while you are sick. If you are sick with COVID-19, avoid contact with your pet, including petting, snuggling, being kissed or licked, and sharing food. If you must care for your pet or be around animals while you are sick, wash your hands before and after you interact with pets and wear a facemask.
Surgical masks are loose fitting, single-use items that cover the nose and mouth. They are used as part of standard precautions to keep splashes or sprays from reaching the mouth and nose of the person wearing them. They also provide some protection from respiratory secretions and are worn when caring for patients on droplet precautions.
Surgical masks can be placed on coughing patients to limit potential dissemination of infectious respiratory secretions from the patient to others
Dr S Thava Seelan
MBBS (Syd), FRACGP, DCH
Master of Public Health & Tropical Medicine (JCU)
Director, Bridgeview Medical Practice, Toongabbie, NSW
Conjoint Senior Lecturer, Western Sydney University