Presence of virus antibodies does not mean you’re immune

A 3-D illustration of an immune system responding to a virus.
A 3-D illustration of an immune system responding to a virus.

Does the presence of Covid-19 coronavirus antibodies in your blood  mean that you are immune to the virus?

According to guidance published by many health authorities, including the UK’s department of health and social care in July, there is no strong evidence yet to suggest that those who’ve had the virus, and have produced antibodies, are immune.

In other words, receiving a positive antibody result does not mean that a person is immune or can’t pass on the virus to others.

But in this past week alone, the UK’s Advertising Standards Authority has upheld complaints of misleading advertising by three clinics in this regard, as the country grapples with a second wave of the outbreak.

In the case of the Solihull Health Check Clinic’s website claim that its test “indicates if your body has developed an immune response [antibodies] to the Covid-19 coronavirus” was technically accurate, the ASA said: “There was no information in the ad itself which explained that a positive antibody result did not mean that a person was immune.

“We therefore concluded that the ad was misleading.

“We told Solihull Health Check Clinic to ensure that they did not state or imply that their Covid-19 antibody test would always detect whether a patient had contracted Covid-19, including by stating that it had ‘100% accurate results’. 

“We told them not to state or imply that a positive antibody test would indicate immunity to Covid-19 where that was not the case.

“We also told them, when advertising their existing antibody test, to include information which clearly stated that it did not indicate immunity to Covid-19.”

Next up was the London Vaccination Clinic, which did a direct marketing campaign via e-mail in late May, with the subject line: “Getting back to work with Covid testing and current services”. 

It claimed: “This simple blood test can tell you within two days whether you have potential antibodies [immunity] to Covid-19”.

In response, the company said it had received five-star reviews on a review website and provided a screenshot of a customer review.”

The ASA wasn’t impressed.

“We noted that there was no information in the ad itself which explained that a positive antibody result did not mean that a person was immune.

“Taking into account government advice on the link between antibody testing and immunity, we concluded that the impression given by the ad, that the tests would indicate whether consumers were immune to Covid-19, was misleading and breached the code.”

The authority’s panel must have had serious déjà vu by the time it got to the paid-for Facebook ad and website for Corona Test Centre London.

It featured an image of several socially distanced people wearing overalls and face masks, and the claim: “We are on a mission to safely get you back to your friends and back to work”, and the claim:  “Antibody testing will tell you if you’ve had the virus and developed an immune response”. 

A study quoted in support of its claims related to the accuracy of the test in detecting antibodies, but did not constitute evidence that the presence of antibodies indicated immunity, which was the message that consumers were likely to take from the ads, the ASA said.

Strike 3 — that advertising claim can’t be repeated either.

In September, Spotlight, the website published by Section27 and the Treatment Action Campaign, reported that initial results from a blood tests conducted in the Cape Town metro indicated that 37% of pregnant women and 42% of people living with HIV had tested positive for Covid-19 antibodies.

“The presence of antibodies in people’s blood sample shows that they had been infected by Sars-CoV-2, the virus that causes Covid-19, and while this indicates some degree of immunity it does not necessarily mean they will be protected from the virus if reinfected,” the report read.

“Though clinical studies are ongoing, there is no certainty of how much protection antibodies offer or for how long.”

In late August, the SA Health Products Regulatory Authority announced its approval of several SARS CoV 2 lab-based antibody test kits.

Health minister Zweli Mkhize cautioned that the detection of antibodies “does not necessarily mean one is immune” and the labs are cautioning consumers about making the leap to immunity.

Pathcare said the results of the tests shouldn’t be used to influence decisions on returning to the workplace or so-called immunity passports.

“It should be noted that there is currently not sufficient evidence to correlate the detection of antibodies with immune protection.

“A positive antibody test result should therefore not be regarded as proof of immunity and must not be used to reduce or abandon protective measures,” the lab said in a press release.

So our Advertising Regulatory Board hasn’t had to stop a local lab from making misleading statements about Covid-19 immunity, but it did have to apply its mind to the claims made by the makers of a Covid-19-related product — a hand sanitiser.

Advanced Product Technology claimed on the label of its Aktivora hand sanitiser that it contained “all-natural plant-based ingredients” when, in fact, it contained more than one chemical ingredient, albeit in small concentrations.

The claim was found to be misleading, and must be removed immediately from the product’s advertising and from its packaging by the end of 2020.

Clearly there’s going to be a demand for Covid-19-related medical products and services for some time yet, so misleading claims are inevitable.

If in doubt, lodge a claim with the Advertising Regulatory Board — it will get to the bottom of whether a claim is backed by evidence or not.

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