MercoPress. South Atlantic News Agency

Third dose of Pfizer coming up globally as Delta variant keeps crawling in

Uruguay's chief vaccinator Dr. Perez Sartori explained the health ministry's priority still was to give everybody a full treatment

The Government of Israel has become the first in the world to decide on the use of a third dose of the Pfizer anticoronavirus vaccine, a move which some other countries are likely to follow suit shortly.

Vaccination is scheduled for next Sunday and will be voluntary for people over 60 years old who have already been immunized with two doses at least five months ago.

Prime Minister Naftali Bennett announced he had consulted with experts in Israel and abroad and they had confirmed that the effectiveness of the first two doses gradually diminishes and that a “booster” would be required.

An international study published Thursday specified that Pfizer's protection falls from 96.2% to 83.7% in six months. The vaccine's efficacy, noted the study published on the MedRxiv website, peaks during the 7-day to 2-month interval after the second dose, gradually decreasing to 83.7% from 4 to 6 months. with an average decrease of 6% every 2 months.

“These vaccines - said the Israeli prime minister - are safe and will be available in a few days.” “The first to receive the third dose will be President Isaac Herzog. I myself will take my mother to to receive the third dose,” Bennett continued.

A European Commission spokesperson has also admitted “that a booster of the vaccine will be necessary and that is why we are preparing, for example, concluding a third agreement with Biontech / Pfizer for 1.8 billion doses that will be needed for a third dose, or to combat variants, or if it will be necessary to vaccinate other groups such as children and young people.” The EC source quoted by ANSA added that “to be prepared we have also opted for another 150 million doses of Moderna.

In Israel the Green Pass has become effective for vaccinated people, for those who have recovered from covid and those who have a negative test for a maximum of 72 hours to participate in indoor events with crowds of more 100. The ”Green Pass” is also required to people over 12 years old to enter cafés, restaurants or other indoor public establishments.

Pfizer said Wednesday through the company website that a third dose of its coronavirus vaccine can increase the neutralization of the Delta variant 100 times and annouced it would ask the FDA to approve this reinforcement in the United States shortly .

Through a document released this Wednesday, Pfizer assured that a third dose would allow the immune response to be “strongly” stimulated. They even estimated that an increase of almost 100 times could be evidenced by the Delta variant after this reinforcement and they anticipated that they would request an emergency authorization, in August, before the Food and Drug Administration (FDA, for its acronym in English) for this new inoculation.

In the documents presented during the “Earnings teleconference for the second quarter of 2021” that is held before shareholders, the pharmaceutical company anticipated what its next steps will be in the framework of the pandemic and carried out special work on the Delta variant, which has already been “Sequenced in 83% of the cases detected in the United States.”

Pfizer claims that after a third dose in relation to the second immunity had grown five times for people aged between 18 and 55 years and of 11 times for those of between 65 and 85 years. Therefore, they assured that the “estimated potential would be an increase of up to 100 times in the neutralization” of this mutation with the application of the “reinforcement”.

Pfizer pointed out a specific batch with a formulation intended for the Delta variant had been developed and for which clinical studies would begin in August.

Although the laboratory acknowledged it would be up to regulatory entities to define who received the booster dose, “it is likely that it will first focus on immunosuppressed older adults” and then on people “over 60 years.”

“Initial data show that the booster dose of the current vaccine (more than six months after the second BNT162b2 immunization) has a tolerability profile and allows neutralization titers against SARS-CoV-2 of between five and eight times higher. for the original strain and between 15 and 21 for the Beta variant (South African),” the Pfizer document stressed.

In addition, the company released a preprint (a document that has not yet been endorsed by peers), where it reported the preliminary results of the studies carried out at six months, indicating that the vaccine “continues to be safe and well tolerated”, since “ few participants had adverse events.”

Regarding the efficacy of the vaccine, the study highlights that, six months after inoculation, there is 91% protection and 97% protection from serious conditions. ”Despite a gradually decreasing trend in vaccine efficacy, BNT162b2 had a favorable safety profile and was highly effective in preventing COVID-19,“ the study concludes.

Meanwhile, Uruguayan health authorities have already authorized Wednesday the supply of a booster dose of Pfizer for those who have received the Sinovac vaccine in the primary scheme. The extra shot will become available at least 90 days after receiving the second dose of Sinovac.

The head of the Health Ministry's Immunizations Unit Graciela Pérez Sartori, explained that the third shot was necessary given the normal decline of these that occurs after the initial peak. ”The peak is greater with the Pfizer vaccine than with the Sinovac vaccine and that will gradually decrease over time in a natural way up to 250 days, that is normal for it to happen.“

She also argued that before the arrival of the variants of concern such as Delta, a greater amount of antibodies is necessary to make a more solid front against them. ”Although there is no community transmission, it is something of concern and with these variants what there is is a greater transmissibility, but in turn a higher antibody titer is necessary,“ she said.

The expert said that Uruguay is in an ”optimal situation“ compared to other countries, because when these variants have entered other places, there is an increase in cases and that the country has a ”window of opportunity” to reinforce its response to viruses through vaccines.

She explained that the 90-day period that was determined is because that is the beginning of the decline in antibodies provided by the Sinovac vaccine, which provides the opportune moment to give the new dose.

She recalled that the agenda will be given in the same way as in the initial scheme and in a staggered manner according to the date on which people were originally vaccinated, with the exception of patients who are on dialysis, who are vaccinated at their center dialysis.

The official nevertheless stressed that the ministry's priority continued to be the people who have not yet completed the vaccination schedule.