Conditions that affect COVID-19 spread 2022

mars 11, 2022

What is COVID-19?

COVID-19 is caused by a coronavirus named SARS-CoV-2 that can affect your lungs, airways and other organs. Coronaviruses are a large and diverse family of viruses which cause illnesses such as the common cold.

SARS-CoV-2 was first recognised in China and is thought to have originated in animals. Other recent diseases caused by coronaviruses and thought to be transmitted from animals include severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS).

COVID-19 variants

The SARS-CoV-2 virus that causes COVID-19 has undergone genetic mutations over time. The Omicron variant has spread worldwide rapidly and is now the major variant in many countries, including New Zealand. Omicron is much more transmissible than previous variants of the COVID-19 virus, including Delta.

Read more about the features of the Omicron and Delta variants. View the latest science and technical advice on COVID-19, including regular variants updates in COVID-19 Science News.

COVID-19 symptoms

Common symptoms of COVID-19 are like those found with illnesses such as a cold or influenza. You may have one or more of the following:

new or worsening cough
sneezing and runny nose
fever
temporary loss of smell or altered sense of taste
sore throat
shortness of breath

Less common symptoms of COVID-19 may include diarrhoea, headache, muscle aches, nausea, vomiting, malaise, chest pain, abdominal pain, joint pain or confusion/irritability. These almost always occur with one or more of the common symptoms.

Symptoms tend to arise around two to five days after a person has been infected but can take up to 14 days to show. The virus can be passed onto others before they know they have it – from up to two days before symptoms develop.

Where to get help

If you develop COVID-19 symptoms get tested immediately. Read more about COVID-19 testing and find your local testing station at Healthpoint. If you test positive you will need to isolate for 10 days.

For most people, symptoms of COVID-19 will be mild and can be managed at home. You can find health advice to help manage your illness on the COVID-19 Health Hub.

If your symptoms get worse or you need urgent medical care, contact your local healthcare provider or call Healthline on 0800 358 5453 24 hours a day, seven days a week.

If you or the person you are caring develops difficulty breathing, severe chest pain, fainting or becomes unconscious, call 111 immediately.

How COVID-19 spreads

The virus that causes COVID-19 is mostly spread in particles that escape from an infected person’s mouth or nose when they breathe, speak, cough, sneeze or sing.

These particles range in size. Larger and heavier particles (droplets) quickly fall to the ground or other surfaces within seconds or minutes. Smaller particles (aerosols) can remain airborne for minutes to hours.

Infection occurs in three main ways:

breathing in air that contains infectious particles
infectious particles landing on your mouth, nose or eyes (for example, through being coughed or sneezed on)
touching your mouth, nose or eyes when your hands have been contaminated by the virus, either through direct contamination, or indirectly by touching surfaces contaminated with the virus.

Current evidence shows the virus that causes COVID-19 (SARS-CoV-2) is spread by aerosols which is why air ventilation is important. Transmission from surfaces is the least common but it is still important to clean surfaces to reduce the risk. Read more about reducing the risk of COVID-19 through air ventilation and cleaning and disinfection.

Conditions that affect COVID-19 spread

A person is most infectious and more likely to spread the virus in the few days around the time that symptoms develop. This means that some individuals can be contagious before they develop symptoms.

The risk of becoming infected increases the closer you are to a person and the longer you are close to that person, especially if this contact occurs in poorly ventilated indoor spaces.

Most large droplets will fall to the ground within 2 metres. However, in some situations the virus has been transmitted to people more than 2 metres away, or to people who passed through a space soon after the infectious person left.

Things that increase the risk of this ‘long-range’ infection include:

being in enclosed spaces with poor ventilation within which fine particles containing virus can build-up
being near an infected person breathing heavily (for example, due to exercise, singing or shouting)
being exposed to these conditions for a longer period of time.

The ‘Three Cs’ are situations where spread of the virus is most likely are:

closed spaces with poor ventilation
crowded places with many people nearby
close-contact settings, especially where people have close-range conversations, singing or shouting.

The risk is highest when these factors overlap: for example, in small, poorly ventilated spaces with lots of people talking loudly or shouting. The risk is lower outside, with fewer people, if they are widely spread.

How to reduce the risk of COVID-19 through air ventilation

Infection and immunity

People are considered likely to be infectious from 48 hours before the onset of symptoms, then for 10 days after the onset of symptoms, and for 72 hours after symptoms have stopped. Some people with severe illness may be infectious for longer.

However, some people who have the virus may not have any symptoms (asymptomatic cases) and could still be infectious. Others may test positive for COVID-19 after they have recovered and no longer have symptoms, but they are unlikely to be infectious beyond 72 hours after their symptoms have ended.

Once a person is infected with COVID-19, their body will usually produce cells (antibodies) that ‘remember’ the virus. We assume these antibodies give the person immunity from the virus, but it is not currently clear how long immunity lasts.

Treatments

COVID-19 infections cause two major issues. The first is the viral attack on the body and the harm that causes, the second is that in some cases the virus also triggers an immune reaction which again can also cause harm.

New treatments being studied now cover both these areas and concentrate on three areas:

Antiviral drugs limiting the ability of the virus to thrive in the body. An example here is Remdesivir which is in use in New Zealand.
Medicines that calm the immune system over-reaction prompted in some patients. An example here is dexamethasone which has been a standard part of our treatment protocols for some time.
Antibody treatments that help the body fight the virus.

Read more about pharmaceutical treatments for COVID-19.

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Conditions that affect COVID-19 spread 2022

What is COVID-19?

COVID-19 variants

COVID-19 symptoms

Where to get help

How COVID-19 spreads

Conditions that affect COVID-19 spread

Infection and immunity

Treatments

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