Production: Pablo Cantudo
In the short time that we have been studying the evolution of COVID-19, we already know many things compared to other previous diseases, such as SARS-CoV-1 in 2003. We already know how it is structured at the molecular level, we know what proteins can induce an immune response, serve to eliminate vaccines or be targets even for viral treatments. “However, we have to be patient,” recalls Quindós. “The four months and little that the pandemic has been evolving is a very short time, we must be cautious.”
In the case of SARS, we know that people who recover have long-lasting immunity, and something similar happens with MERS, both coronaviruses very close to the one that causes COVID-19. We could have the same luck as with the previous two and induce a long-lasting immunity. On the other hand, as Quindós recalls, other coronaviruses that cause approximately a third of common colds that, nevertheless, give us problems, albeit mild, annually. “ So what is going to happen to SARS-CoV-2? We do not know. There are very optimistic people who think that we will develop long-lasting immunity or that the virus will even disappear; and there are those who believe that we are going to develop a temporary immunity, that, over time, new cases will appear every year or every two years ”.
What we know today is that in infected monkeys and mice an immunity does occur, mediated by antibodies, which inhibits reinfection for about 40 days; but we don’t have long-term data yet. “Observing these data, I tend to be optimistic, but not too optimistic, because it is likely that this wave that we are experiencing is not going to be the only one,” acknowledges Quindós, and continues pointing out that it is possible that the epidemiological studies that will be carried out soon population to calculate group immunity (which stands at 60%) may leave us “a bit uncomfortable” (after recording this interview, we knew the news that only 5% of Spaniards have developed immunity against COVID-19).
“If COVID-19 has only been through so few people, it is inevitable that we will suffer a second wave, possibly in the fall or winter .” However, even if the percentage of people who have developed immunity, even if it is small, will slightly dampen the outbreak, and the second wave is probably not so serious. “But everything is estimates, probabilities. And there are them for all the tastes ”, remembers Quindós.
As Quindós explains, SARS-CoV-2 not only develops humoral immunity (mediated by antibodies), but also cellular immunity; The latter will be the most effective in protecting us against COVID-19.
Quindós also offers us detailed information on how to interpret the COVID-19 diagnostic tests.
- PCR test : detects the RNA of the virus in our body; confirms infection.
- IgM test : detects the presence of immunoglobin M antibodies in the acute phase of the disease.
- IgG test : detects the presence of immunoglobin G antibodies in the recovery phase of the disease. It may take up to 14 days to be detected. The longer this phase lasts, the more likely it is to be cured and not to be contagious.
Clues to the ‘new normal’ : Guillermo emphasizes that, in post-COVID-19 society, we must improve our capacity for detection, tracking, diagnosis, as well as preparing health systems with sufficient resources to care for all those affected.
Some studies on immunity and COVID-19:
Robert D. Kirkcaldy. ‘COVID-19 and Postinfection ImmunityLimited Evidence, Many Remaining Questions’. JAMA. (May 11, 2020). doi:10.1001/jama.2020.7869
Sarah Ee Fang Yong. ‘Connecting clusters of COVID-19: an epidemiological and serological investigation’. Lancet Infect Dis (April 21, 2020) https://doi.org/10.1016/ S1473-3099(20)30273-5
Nandini Sethuraman. ‘Interpreting Diagnostic Tests for SARS-CoV-2′. JAMA. (May 6, 2020). doi:10.1001/jama.2020.8259
(PREPRINT) Ludivine Grzelak. ‘SARS-CoV-2 serological analysis of COVID-19 hospitalized patients, pauci-symptomatic individuals and blood donors’. MedRXiv (2020) doi: https://doi.org/10.1101/2020.04.21.20068858
