Immunity passports, no scientific evidence to back them up yet

There is no clear scientific evidence yet to back the immunity passport initiative. Even so, countries like Chile are betting on this path.

Chile announced that it will begin implementing immunity passports to control mobility. On April 17, the Ministry of Health of that country reported that those citizens who have already been infected with the virus will be certified as a guarantee that they already have immunity and, therefore, can resume their jobs.

This proposal was the topic of conversation in the live streaming space through YouTube of El Espectador, on Tuesday, April 21. The panel included Julián Fernández Niño, professor in the Uninorte Department of Public Health; Tatiana Andia, sociologist and researcher at the Universidad de los Andes; Andrés Vecino, from the Johns Hopkins University School of Public Health; and Gabriela Delgado, PhD in Pharmaceutical Sciences and professor at the National University.

The debate, moderated by the editor of Science and Technology, Pablo Correa, focused on analyzing the proposal. According to the panelists, it can be problematic due to its epidemiological and social implications. For Delgado, one of the biggest concerns is which test to use to demonstrate not only that the person is no longer ill, but also that he is not infectious to others.

To think that after contracting coronavirus, immediate immunity is acquired, is a presumption that this virus acts like other respiratory viruses, however, it is not clear what is the specific participation of the immune response in virus control. “It has been discussed in recent articles that the immune response in some individuals who have cleared the virus and are no longer infectious is not necessarily detectable. Apparently it is not mediated only by antibodies but also by a cellular response, “Delgado noted.

One of the major concerns that arise is that serological, or rapid, tests be used, which in addition to having a significant margin of error, do not give the complete picture in terms of immunity. For Fernández, more studies and more time are still needed to fully understand how the disease works and the tests we are using to detect it.

The WHO has ruled on the use of rapid tests and stated that the application is very limited and that they may be useful in serological surveys for epidemiological monitoring. “Part of the problem is that there are not enough longitudinal cohort studies to know how effective natural immunity is after infection and how long it lasts over time,” added the teacher from the Uninorte Department of Public Health. (See: What are rapid tests for and what are they not for?)

According to Vecino, there is no scientific evidence yet to back the immunity passport initiative. He noted that a presumption is being made by equating COVID-19 to Sars. However, he argued that there is a very varied range of responses to viruses. For example, in the particular case of Sars, according to a 2007 study, immunity disappears every three years. But we also know about viruses like HIV, which produces antibodies that do not protect against the disease.

“When the tests are validated, they will play a role in knowing how much we become infected, but it is very risky to introduce the use of the presence of antibodies, even if they were protective, as a way of segmenting the population in the absence of a vaccine,” said.

For the Johns Hopkins School of Public Health teacher, this decision is due to the state of emergency we are in, and the demand to revive the economy that leads leaders to make hasty decisions, which are not supported by robust scientific evidence , reviewed and validated by peers.

From the social sphere, the proposal of the immunity passport could be a window to deepen inequalities. Andia commented that benefiting those who have contracted the disease over those who do not have implications that may be worse than current ones with compulsory isolation, especially in middle-income countries, where a large part of the workforce is in their hands. poorly trained work.

The sociologist explained that this proposal would be risky for those who have physical jobs, since it generates another level of segregation among those who need to work, while configuring a privilege for the immune, and a decrease in income for people who do not have contracted the disease. Andia complemented that, due to its complexity, the concept of immunity is dangerous, since it begins to associate with more available social references —as happened with leprosy and yellow fever—, which promote division.