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Why does the KnowNowᵀᴹ test use a saliva sample?

We chose to design our unique KnowNowᵀᴹ test for COVID-19 infectiousness to work with a simple saliva sample, so that it would be comfortable and easy to administer, and to ensure that anyone would be happy to take a test every day if required. We believe that patient comfort and happiness leads to increased participation in routine testing, and ultimately increases the probability that COVID positive patients can be detected before they've had a chance to infect others.

The focus of our first clinical study was to assess the feasibility of using saliva sampling, to refine our saliva collection method, and also to assess the overall usability of the KnowNow test. This was a UK Government-supported National Institute for Health Research (NIHR) study carried out across ten UK hospitals with 100 patients participating. Through this study we determined that saliva sampling was both effective and user-friendly, and identified a specific swab for sampling. We chose not to opt for a spit collection method for our saliva sample, as providing a spit sample can be challenging for some patients, particularly the elderly or those suffering with COVID-19 symptoms.

For other COVID-19 tests, throat and nasopharyngeal swabbing is one of the most common types of sample collection. However, a number of studies have explored various issues with these types of sample collection, including:

  • The sample collection method requires a swab to be inserted into the patient's throat and/or far into their nostril and rotated, causing discomfort to patients due to the procedure’s invasiveness, and even inducing bleeding in their tonsils and posterior pharynx. (1)
  • The discomfort or even pain of the sample collection method has a detrimental impact on compliance for serial testing, as patients are unwilling to subject themselves to the test on a regular basis. (2)
  • Nasopharyngeal sample collection presents a considerable risk to healthcare workers, because it can induce patients to sneeze or cough, expelling virus particles. (2)
  • There are several situations where nasopharyngeal swabs would cause particular harm, such as in patients with coagulopathy, those undergoing anticoagulant therapy, or those with significant nasal septum deviation. (3)
  • These tests are not always successful at the first attempt, even though performed by trained healthcare workers, and shortages of swabs and protective equipment are frequently reported. (3)
  • They show relatively poor sensitivity for SARS-CoV-2 detection in early infection and are inconsistent during serial testing. (2)

Some tests have been designed to work with anterior nasal swabs, as a somewhat less invasive alternative to nasopharyngeal swabs. However, there is some evidence to suggest that nasal swab testing produces less sensitive results and may miss patients with lower viral loads (4).

References:

(1) Exploring salivary diagnostics in COVID-19: a scoping review and research suggestions

(2) Saliva is more sensitive for SARS-CoV-2 detection in COVID-19 patients than nasopharyngeal swabs

(3) Saliva as a Candidate for COVID-19 Diagnostic Testing: A Meta-Analysis

(4) Nasal-Swab Testing Misses Patients with Low SARS-CoV-2 Viral Loads

How long can unused KnowNowᵀᴹ Tests be kept before they expire?

The expiry date of KnowNowᵀᴹ Tests will be clearly marked on their packaging, and you can expect the shelf-life of each box of tests to be at least four months.

How does KnowNowᵀᴹ compare to COVID-19 antibody tests?

The KnowNowᵀᴹ Test and COVID-19 antibody tests test for completely different things.

Antibody tests identify whether someone has had coronavirus in the past, whereas the KnowNowᵀᴹ Test detects whether an individual is currently infectious.

Antibody testing involves detecting the immune response in the human body to having fought off a virus. These tests look for an antibody created in the bloodstream in response to the presence of a virus in that environment. This is useful when testing the effectiveness of a vaccine, or understanding how far and wide a virus has spread. However, it is of limited usefulness to individuals, as it is only able to identify whether an individual has fought off the SARS-CoV-2 virus in the past. It cannot effectively confirm whether they are currently infected, or infectious.

How soon after exposure would the KnowNowᵀᴹ Test give a positive result?

The KnowNowᵀᴹ test will show a positive result from day 3 or 4 after exposure to the SARS-CoV-2 virus. This is earlier than other rapid antigen tests, which usually start to show positive results around day 5 or later.

This also means that individuals will receive a positive KnowNowᵀᴹ test 1 or 2 days before they are at very high risk of infecting others. So where there is a regular testing programme in place, individuals can quickly be isolated before they become highly infectious and the spread of the virus can be prevented.

The basis for this is our analysis of models of viral load in disease progression, such as the one shown within "Test sensitivity is secondary to frequency and turnaround time for COVID-19 screening" by Dr Michael Mina et al, alongside the low limit of detection of the KnowNowᵀᴹ test of 50,000 to 200,000 viral copies per mL.

How long does a negative test result last for?

Receiving a negative result means that the individual tested does not have any live virus in the sample provided and is not currently infectious to others. However, it's important to be aware that they could still be exposed to the SARS-CoV-2 virus following the test. It could also be possible that the individual tested has already been exposed to the virus 1 or 2 days ago, and they have not yet become infectious to others.

As a result, we recommend that individuals are tested as regularly as possible to keep workplaces and communities safe. Depending on the scenario, we would recommend testing is repeated every 1 to 3 days.

How should KnowNowᵀᴹ tests be stored?

KnowNowᵀᴹ Tests should be stored between 2 and 30 degrees celsius, which means it's fine to store it at room temperature in the UK's mild climate.

There's no need to store it inside a fridge, unless you're expecting extremely hot weather. If you do choose to refrigerate the test though, just make sure it comes to room temperature before using it.

The KnowNowᵀᴹ Test device should also be stored still sealed in its foil pouch. Once removed from the foil pouch, it should be used within one hour.

I've already activated my sample pack

If you have already activated your sample pack please go to the activation link that we emailed to you. Alternatively, if you fill in your email again we will re-send the activation link to you.

How big is a KnowNowᵀᴹ Test kit?

One box contains 25 tests, and measures 20cm (L) x 21cm (W) x 8cm (H).

Is there a limit to how frequently I can take your tests?

No, there's no limit at all. KnowNow is specifically designed for frequent testing in order to offer the best chance of identifying infectious individuals as early as possible.

We recommend that individuals are tested as regularly as possible to keep workplaces and communities safe. Depending on the scenario, we would recommend that testing is performed every 2-3 days, or even daily, depending on the scenario.

What does a positive test result look like and mean?

Positive KnowNowᵀᴹ Test result
Positive KnowNowᵀᴹ Test Result

If there is one red line visible next to the "C" in the KnowNowᵀᴹ device test results window, and any line at all, no matter how faint, appears next to the "T", then the test result is positive. This indicates that the SARS-CoV-2 antigen has been detected in the sample.

Following a positive result, current government guidance on matters including self-isolation and reporting the result should be followed.

Who is Vatic?

Vatic is a predictive health company focused on making medicine more proactive. We deliver on-the-spot tests which detect subtle biomarkers in people’s bodies to predict illness before it becomes acute or infectious.

Our first product is KnowNowᵀᴹ, a rapid turnaround COVID-19 antigen test, that is designed to identify COVID-positive people before they become highly infectious*, based on just a small saliva sample.

Had COVID - 19 symptoms in the last 2 days? Apply here to help us make testing accessible to all.