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CIDRAP- COVID-19 Scan for Sep 22, 2022- Previous infection and COVID protection;  Global Paxlovid access agreement

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  • CIDRAP- COVID-19 Scan for Sep 22, 2022- Previous infection and COVID protection;  Global Paxlovid access agreement

    COVID-19 Scan for Sep 22, 2022

    Previous infection and COVID protection;
    Global Paxlovid access agreement

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    Study shows previous Omicron infection most protective against BA.2

    A study in The Lancet Infectious Diseases demonstrates that previous Omicron BA.1 infection was the most protective factor against BA.2 infection (associated with a risk reduction of 72%) and gave greater protection than primary infection with pre-Omicron SARS-CoV-2 (38%) or three doses of an mRNA vaccine in people with no previous infection (46%).

    The test-negative case-control study involved Quebec healthcare workers to compare those who had a positive SARS-CoV-2 test during the period of Omicron BA.2 dominance, from Mar 27 to Jun 4, 2022, with healthcare workers who had a negative test during the same period.

    The primary COVID-19 infection had to take place at least 30 days before the study period, with pre-Omicron infections occurring between Feb 20, 2020, and Nov 27, 2021. Omicron BA.1 attribution was given for all cases between Dec 26, 2021, and Mar 26, 2022. In total, 37,732 presumed Omicron BA.2 cases were compared with 73,507 randomly selected controls.

    The authors said that among cases, 1,159 (3.1%) had a primary infection combined with two mRNA vaccine doses, and 1,436 (3.8%) had a primary infection and three vaccine doses. Among controls, 687 (10.9%) had a primary infection combined with two vaccine doses, and 821 (13.4%) had a primary infection and three vaccine doses.

    Hybrid immunity from BA.1 infection plus two or three mRNA vaccine doses increased effectiveness to 96% for longer than 5 months. Notably, a third vaccine dose conferred no improvement to that hybrid protection.

    "These data provide immunological context for the importance of hybrid immunity in managing the current surges caused by the BA.2.12.1, BA.4, and BA.5 subvariants in populations with high frequencies of vaccination and BA.1 or BA.2 infection," writes David Hui, MD, of the Chinese University of Hong Kong, in a commentary on the study. "Another important factor in reducing infection risk is heterologous booster vaccination with different platforms to maximise the breadth of vaccine-induced immunity, especially in countries primarily using inactivated vaccine."
    Sep 21 Lancet Infect Dis study and commentary

    Agreement paves way for greater global Paxlovid access

    Pfizer today announced that it has signed an agreement with the Global Fund to supply up to 6 million Paxlovid courses for 132 low- and middle-income countries to help treat COVID-19.

    The countries will be able to access the drug through the Global Fund's existing pandemic response mechanism, which has been used to provide grant support for tests, treatments, personal protective equipment, and other elements for strengthening heathcare systems.

    In a statement, Pfizer said it expects the supply to begin this year, based on regulatory approval and country demand. Countries can buy supplies through tiered pricing at Pfizer's nonprofit rate. Albert Bourla, Pfizer's chief executive officer, said the contact with the Global Fund boosts equitable access to treatments for high-risk groups in low- and middle-income countries. The company also said the agreement builds on earlier efforts to ease access.

    In US developments, an official with the Food and Drug Administration said this week that updated COVID boosters for children ages 5 to 11 years old will be authorized in the coming weeks, according to ABC News. Peter Marks, MD, PhD, who directs the FDA's Center for Biologics Evaluation and Research, was speaking at an event with the COVID-19 Vaccine Education and Equity Project. Earlier this month, the new booster was cleared for emergency use in people as young as 12.
    Sep 22 Pfizer statement
    Sep 21 ABC News story