Antibody tests can be a game-changer against COVID-19 because they would show not only who has the disease — but who had it in the past and is potentially immunized. It’s an important step, but there are still many questions.

Antibody tests

Researchers all around the world are working to develop and produce better and faster diagnosis tests. We need as many such tests as possible if we are to have an idea about who is infected and how the disease is spreading.

But another type of test is also important: the antibody test.

Part of the reason why SARS-CoV-2 can be so damaging to the human body is that there is no innate immunity to it — we are “immunologically naive” to it. When a virus attacks the human body, the body typically reacts by producing antibodies. After the infection is overcome, the antibodies stay inside the body (either for a while or forever). A serological test looking for those antibodies could indicate whether someone has had the disease — potentially even without knowing it since, many times, SARS-CoV-2 carriers are asymptomatic.

Evidence for the first type of test emerged in early February in a study published by Chinese scientists. Researchers in Singapore followed suit just 3 weeks later, and there are currently massive efforts by universities, companies and health organizations such as the CDC to develop and produce such tests. The UK government has reportedly ordered 3.5 million such tests which will hit the shelves “in a matter of days
“.

It’s curious that the UK has announced that these tests will be available on “Amazon” and “other online platforms” instead of being used specifically on key groups such as medical staff and essential workers, but if the announcement holds true, it is encouraging news nonetheless.

Immunity

The assumption that these tests are effective hinges on the theory that infected humans develop immunity to SARS-CoV-2. There is evidence to support this, but it’s not ironclad.

A small study on macaques (that has not yet been peer-reviewed) reports that reinfection was not possible. Furthermore, antibodies have been detected in the blood of recovered patients — and some healthcare providers are even considering antibody-rich plasma as a treatment in some cases.

But there are earlier reports of reinfection in China, as well as several cases in Japan. It might be that faulty tests and not reinfection is at play, but, at the moment, it’s impossible to say. Most epidemiologists believe that, at least in most cases, there will be some type of immunity gained — even if it is temporary. There’s also the encouraging news that the coronavirus is apparently mutating slowly, which suggests that there will be likely few new strains.

It will be a while before we have a vaccine for COVID-19. The first step in understanding the disease is currently to deploy as many diagnostic tests as possible, especially to people displaying severe symptoms and in key positions (ie doctors and nurses). The next step is to start figuring out who has COVID-19 antibodies. This would be important in two ways: it would help us understand how the disease has spread (and just how many cases were indeed asymptomatic), and perhaps more important in the short run, it would tell us who is immunized and can potentially re-enter society.

Then, we have to see how long this immunity lasts. It could be a lifetime, years, or maybe just a few months. Ultimately, we will have a vaccine for this, but we’re looking at 12 months in an optimistic scenario. In the meantime, we must save as many lives as possible, understand as much as we can about this outbreak, and find ways to keep society going during the pandemic. It’s a massive challenge, but mankind is better prepared than ever.