What is Long Covid? | What are mRNA and Viral Vector-Based Vaccines?
What is antibody/serological testing? | What is a social bubble/circle? | What is contact tracing?
What is respiratory transmission vs fomite-mediated transmission? | What is Hydroxychloroquine?
What is herd immunity? | What is a Super Spreader?
This page contains key terms that are emerging in research literature and news reports about COVID-19.
Early attention has been on the acute illness generated by the virus, but it is becoming clear that, for some people, COVID-19 is a long-term illness, and this condition has become known as Long Covid. Many people are finding they are still unwell more than 4 weeks after the start of their infection, and some develop new problems over several weeks. The most common signs and symptoms that linger over time include:
Sources: NIHR "Living with Covid19", Mayo Clinic COVID-19 (coronavirus): Long-term effects, & NICE COVID-19 rapid guideline: managing the long-term effects of COVID-19
Many vaccines are being studied to see if they will prevent COVID-19, and most COVID-19 vaccines being developed help the body develop an immune response against what's called the spike protein on the outside of the coronavirus.
Viral vector-based vaccines use a harmless virus (in this case, the adenovirus) as a delivery system. Once injected into the body, the virus contained within the vaccine produces the SARS-CoV-2 spike protein. This protein doesn't make you sick. It does its job and then goes away. Through this process, the body is able to mount a strong immune response against the spike protein without exposing you to the virus that causes COVID-19.
mRNA vaccines are a new type of vaccine. They teach our cells how to make a protein that will trigger an immune response. Once triggered, our body then makes antibodies. These antibodies help us fight the infection if the real virus does enter our body in the future. The mRNA molecule is essentially a recipe, telling the cells of the body how to make the spike protein.
As of December 9, 2020, Health Canada authorized the Pfizer-BioNTech COVID-19 mRNA vaccine (Tozinameran or BNT162b2) with conditions under the Interim Order Respecting the Importation, Sale and Advertising of Drugs for Use in Relation to COVID-19.
Sources: COVID-19 Vaccines, Government of Canada | Image Source: Unsplash by Daniel Schludi
An antibody (serology) test is a blood test that checks for antibodies which can reveal if you have had an infection, such as COVID-19. Antibodies are proteins that help fight off infections.
Antibody tests are important as they provide information on how widely spread COVID-19 is. Health Canada states that they "can be useful in assessing the population that contracted the disease by detecting the antibodies developed against the virus.”
However, it's important to note that the Centers for Disease Control (CDC) cautions that antibody tests "should not be used to diagnose someone as being currently sick with COVID-19. To see if you have a current infection, you need a viral test, which checks respiratory samples, such as a swab from inside your nose." (More from the CDC on antibody testing here).
Getting a positive antibody test result also does not necessarily mean that a person is immune to COVID-19 and can't be re-infected, as research is still ongoing on about COVID-19 antibodies and how much protection they may offer in the short or longterm.
(Sources: CDC "Serology Testing for COVID-19 at CDC", CDC "Test for Past Infection", HealthLine)
On Friday June 12th, the Ontario government announced that citizens can now form “social bubbles” or “social circles”. This means that individuals can now form a “group” that consists of 10 people whom they can come into close contact with, including hugging. The government's guidelines for safely forming a social bubble/circle can be read here. An important point to remember when forming a social bubble/circle is that the members of the group agree to only have one social bubble. Each member should practice physical distancing (remaining 6 ft apart) when in contact with others that are not part of the social bubble/circle.
Contact tracing is a preventative method that is used to "trace" who individuals that have tested positive for a contagious disease (such as COVID-19) have been in contact with. Once an individual has been confirmed positive with a disease, this is how the people they have been in contact with are generally contacted:
Healthcare workers try to contact anyone who has come into close distance (usually within 6ft for 5-10 mins) of the infected individual and informs them that they may have been exposed; OR instructions are given on what to do next such as staying aware of symptoms & self-isolating to prevent further spread.
Dr. Laura Breeher, medical director of occupational health services at the Mayo Clinic says that “it’s having a moment of glory right now [...] because of the crucial importance of identifying those individuals who have been exposed quickly and isolating or quarantining them."
By comparison, digital contact tracing using technologies such as Bluetooth or GPS tracking is being explored, in order to help automate parts of this process, although privacy is a concern. There are a variety of different models currently being explored by companies like Apple and Google and governments.
(Sources: Time "What is Contact Tracing?" & CDC Digital Contact Tracing Tools for COVID-19)
COVID-19 "is primarily transmitted between people through respiratory droplets and contact routes", aka respiratory transmission, according to the WHO and current evidence. Transmission (passing) of the virus through droplets can occur when having fairly close contact (1 metre or less) with another person who coughs or sneezes, thereby transmitting infected particles into the air which can then contaminate a person through exposure of their mouth, nose, and/or eyes.
There are a few ways you can protect yourself from contracting COVID-19 through respiratory transmission:
Indirect, fomite-mediated transmission can also occur through fomites (objects or materials) that have been infected by someone who is ill. For example, the cold virus spreads easily when people touch door handles that are infected by one's sneeze. Infection Control Today (ICT) writes that "fomite-mediated transmission can be an important pathway causing significant disease transmission in number of settings such as schools, daycare centers and long-term care facilities.”
There are a few ways you can protect yourself from contracting COVID-19 through fomite-mediated transmission:
(Source: World Health Organization, Very Well Health & Infection Control Today | Image source: https://pixabay.com/photos/disinfection-door-knob-alcohol-4977412/)
Pronounced hye drox ee klor' oh kwin & klor’ oh kwin.
Hydroxychloroquine (Plaquenil) is an antimalarial drug, typically used to prevent & treat acute attacks of malaria, though the medication has also been used as a treatment in lupus, rheumatoid arthritis and other illnesses. Chloroquine (Aralen) is also an anti-malarial drug, used to treat amebiasis that has spread outside the intestines and several forms of malaria.
There has recently been a lot of news coverage on hydroxychloroquine as a potential treatment for COVID-19. While the U.S. Food and Drug Administration has authorized emergency use of both drugs for COVID-19 patients, it is important to note that to date, there has been no scientifically proven evidence that supports the effectiveness of hydroxychloroquine against COVID-19.
As well, a Science magazine article (April 21, 2020) notes that the initial study that prompted exploration of this drug as a COVID-19 treatment has been considered flawed by fellow scientists; moreover, several clinical trials haven't been able to prove these drugs' effectiveness against COVID-19, and one preprint study on veterans found an increased risk of death for those who received treatment with hydroxychloroquine.
Sources: MedlinePlus, Science, and MedicineNet
Herd immunity (or herd protection) refers to the indirect protection non-immune individuals receive when the majority of a population is immune to an infectious disease, such as COVID-19. Johns Hopkins provides the illustrative example stating that "if 80% of a population is immune to a virus, four out of every five people who encounter someone with the disease won’t get sick (and won’t spread the disease any further). In this way, the spread of infectious diseases is kept under control. To achieve herd immunity, a large proportion of the population has to either get infected or get vaccinated.
In terms of achieving herd immunity for COVID-19, Johns Hopkins states that "Based on early estimates [...] we will likely need at least 70% of the population to be immune to have herd protection. They outline the most likely case is between the best and worse case scenarios as"where infection rates rise and fall over time; we may relax social distancing measures when numbers of infections fall, and then may need to re-implement these measures as numbers increase again. Prolonged effort will be required to prevent major outbreaks until a vaccine is developed. Even then, SARS-CoV-2 could still infect children before they can be vaccinated or adults after their immunity wanes." If the novel coronavirus acts like other coronaviruses (such as the seasonal flu) it is expected that those who have been infected might remain immune for months to years, but not necessarily for their entire lives.
A super-spreader is defined as "a highly infectious person who spreads the agent of an infectious disease to many other people". It is not clear how one person can become a super spreader, though there are speculations that "it is likely to be caused by multiple factors, possibly including getting a higher dose of the virus in the first place or being infected with more than one pathogen".
There are super-spreaders of the novel coronavirus that causes the disease COVID-19. It is believed that among super spreaders there is a "20/80 rule" meaning that "a small core group of about one in five people transmit infections to far more people than the majority do". Learn more about super spreaders here.
Sources: MedicineNet & The Guardian | Image source: SELF ISOLATE IF YOU FEEL UNWELL. by Russell Tate via Unsplash
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