Covid vaccine with extended validity leads to dropouts in SP

Press advisor Andréa Duarte, 52, sought out a health center in the east of São Paulo last Monday (18) to take the fourth dose of the Covid-19 vaccine. The only one available was from Astrazeneca, whose batch had expired in May, but is being applied after Anvisa (National Health Surveillance Agency) authorized the extension of the expiration date. She refused to take the expired dose.

“I went to the same post where I took the other three doses of Pfizer. I would even take Astrazeneca, but an expired vaccine is asking too much,” he said.

The advisor’s husband, Ricardo Paulino, 53, also refused to take the expired vaccine. “The expiration date of vaccines is to be respected”, he says.

On April 11 of this year, Anvisa authorized the extension of the expiration date of dozens of Astrazeneca vaccine batches, manufactured by Fiocruz between July 2021 and January 2022.

With the change, the validity goes from six to nine months from the date of manufacture. The batches that are being applied this month had an initial expiration date between April 2 and May 2.

The list with all the batches that underwent alteration can be consulted on the Anvisa website.

Regular tests determine the validity of a vaccine and also whether it is possible to extend this period, says Celso Granato, an infectious disease specialist in Clinical Pathology at the SBPC/ML (Brazilian Society of Clinical Pathology / Laboratory Medicine).

“The expired vaccine can be used. The expiry date is calculated from a time acceleration process to estimate how long the immunizer will last. It is done by exposing the vaccine to a higher temperature, followed by tests in the laboratory to measure the effectiveness”, says Granato.

Businesswoman Leine Okoda, 50, and her husband, music producer Cristiano Borges, 48, are looking for “any vaccine other than Astrazeneca” to avoid possible side effects of a fourth dose. Okoda says that the expired batch with an extended shelf life is not a determining factor in the search.

“The problem is that I have acquaintances who were hospitalized due to a reaction to the Astrazeneca vaccine even though they had taken previous doses from the same manufacturer. In the first doses, they had mild reactions, but in the last one it was very strong”, he says.

The couple is leaving for the United States in two weeks and fears that mild symptoms similar to those of Covid-19 caused by the reaction to the Fiocruz vaccine could spoil and even prevent the trip.

They went through two health posts in the west of São Paulo in search of other options. They didn’t. “Apparently there’s only Astrazeneca,” says Cristiano.

The fear of an unusual reaction when taking the expired vaccine was also a decisive factor for Andréa. She points out that she believes in science and that people should get vaccinated, but that the lack of information about whether there was any risk in taking an expired vaccine made her fearful of dying. “What if I had a heart attack? We don’t know if the side effects of an expired vaccine are the same as the others. “Will it really protect me if I take an expired vaccine?”

The SBPC infectologist says that yes, the vaccine will protect, and points out that it is common for pharmaceutical companies to ask regulatory agencies to extend the expiration date of vaccines after having results of new tests that indicate there is greater resistance of immunizers than expected.

In addition, in general, the main effects of Covid vaccines used in the country are pain at the application site, feverish sensation, malaise, body pain and flu. Typically, these symptoms disappear within 24 hours, at most lasting two days.

According to the leaflet of immunizers, most of these milder symptoms can be felt around 10% of those who use the drugs.