Are ‘immunity passports’ a good idea?

Vaccines against COVID-19 are being launched in England and will soon follow elsewhere. This is great news, but just the beginning of a long program that could run through mid-2021 and beyond. Meanwhile, the number of people protected from symptomatic COVID will steadily increase as more people are vaccinated.

The economy will not suddenly restart with the first injections on December 8, but could it slowly reopen, perhaps allowing those who have been vaccinated to return to normal life?

The idea of ​​”immunity passports”, documents that certify whether someone has received the COVID vaccine or has recovered from the disease and can be used to allow entry into a country or establishment, has been debated throughout the year. Some governments have already adopted the concept.

Read more: Vaccines are here, but how will we get them to billions of people?

The UK NHS has created a card for people who have received the vaccine, indicating the name of the vaccine, the batch number and the date of the vaccine administered. There is space for this information in the first and second doses. The card says in bold: “Be sure to keep this registration card in your purse or wallet.”

This card will allow the NHS to keep track of vaccination dates and should not be considered an immunity passport. In fact, the country’s health secretary, Matt Hancock, told Sky News that the government had no plans for the card to act as a passport. But that won’t necessarily prevent companies or other countries from treating it as such.

Vaccines and immune protection

Immunity passports were first discussed early in the pandemic when it was shown that people who survived COVID-19 had evidence of antibodies or T cells, or both, that were specific to the virus. Some people assumed that because these are signs of protective immunity for some other viruses, they probably also meant protection against SARS-CoV-2, the virus that causes COVID-19. But at this point, we couldn’t predict for sure what would happen to people who were exposed to the virus a second time, so immunity passports were definitely not a good idea.

We now know that vaccines can induce protective immunity by initiating an early response to part of the coronavirus known as its peak protein. However, data on people protected after vaccination has not yet been published. This is important because if we don’t understand the key ingredients for protection, we can’t effectively monitor immunity.

For example, is having antibodies that target coronavirus spike proteins enough to protect against reinfection? Also, are the thresholds for protective immunity the same in the young and the elderly and in specific groups, such as the immunosuppressed?

We need to know how we can monitor immunity to begin to understand who is likely to be safe, and for how long, after vaccination. Without this, immunity passports or equivalents can only tell us when someone was vaccinated or infected, not if they are still protected.

Are vaccinated people still contagious?

Assuming that if we have the seal of protective immunity we can consider ourselves safe, what does this mean for those around us? An effective immunity passport can be very attractive for activities such as flying, going to the theater or even going to restaurants, pubs and clubs.

Read more: The Pfizer vaccine has just been approved: this will be the next few months

A key goal of vaccines is to reduce the chance of serious illness for the vaccinated person and to reduce the risk of death from the disease they were vaccinated against. This is possible because vaccination leads to a rapid immune response when we become infected with the virus, since our immune system has been primed by the vaccine.

An earlier response also reduces the time we are infected and this, in turn, can reduce the time we are clearing the infectious virus. However, vaccinated people can still transmit the infection, and we must collect evidence after the vaccines are implemented to measure whether the vaccines can confer sterilizing immunity and eliminate transmission. The Oxford-AstraZeneca vaccine trial may also have data that addresses this question, but this has yet to be reported.

To protect those around us, we would have to keep wearing a mask and keep our distance after being vaccinated, until vaccines are available to everyone or until we understand who can protect themselves. Being personally protected after a successful vaccination does not exempt us from social responsibility.

Run away, little virus

Here comes the good news: when vaccination reaches more than 70-80% of the population, the virus will run out of places to hide. This is how we eradicated smallpox in the past, how we reduced polio cases close to eradication, and how we can eliminate SARS-CoV-2 as a threat to humanity.

Even in the absence of sterilizing immunity, reducing the viral load and duration of infection in vaccinated people will help reduce transmission.

To achieve this, we need to reach the viral carriers that drive transmission rates and they may not be the same people as the vulnerable groups that will be vaccinated first. These may be the young, who are at a lower risk of death from this disease, but can transmit it well in super-spread events.

When we understand “correlates of protection,” the biological markers that correlate with protection against disease, some form of passport-type immune monitoring may be possible to help us stay up-to-date with booster vaccines to protect the vaccinated person. But we must work together to ensure the protection of others. Combined with measures to prevent transmission, vaccination will help control the virus and we can return to life as we know it, although this time, much wiser.