Mary Wilson
Well-known member
Favored shot is a seemingly safer smallpox vaccine, but efficacy remains unclear
7 JUN 2022 6:05 PM
BY KAI KUPFERSCHMIDT
... Now, this virus, further weakened and brought to the market by the Danish pharma company Bavarian Nordic, may become key to arresting the largest outbreak of monkeypox ever seen outside Africa, which has already sickened more than 1000 people. It is the only vaccine licensed anywhere for use against monkeypox, although other, riskier smallpox vaccines also appear to offer some protection. The United States, the United Kingdom, Canada, and several other countries have already started to “ring” vaccinate, offering it to contacts of identified monkeypox cases, including health care workers and sexual partners. “MVA will be very important in this outbreak because it is a nonreplicating vaccine, which means it doesn’t have the same side effect profile as some of the other live [virus] vaccines” being considered, says Rosamund Lewis, technical lead on monkeypox at the World Health Organization (WHO).
But what role the vaccine will ultimately play depends on a host of factors: whether those most at risk from infection can be identified and vaccinated, whether the vaccine is as effective as hoped, and whether enough is available to stop the burgeoning outbreak. WHO has so far only backed ring vaccination—MVA is ideally given within 4 days of an exposure but recommended for up to 14 days—but some scientists say it’s too difficult to reach the specific contacts people had. They advocate broader vaccination campaigns in the population most affected so far: men who have sex with men (MSM).
... Bavarian Nordic’s nonreplicating vaccine, marketed as Jynneos in the United States and as Imvanex in Europe, sidesteps some of the risk. So does a vaccinia-based vaccine named LC16m8, licensed for smallpox only in Japan, which also appears to cause fewer side effects. “I believe these are the ones that are going to be used [in the new outbreak] because they have a much-enhanced safety profile,” says Marion Gruber, who headed the U.S. Food and Drug Administration’s vaccine office until October 2021.
Canada and the United States have already licensed MVA for use against monkeypox and Bavarian Nordic is in talks with the European Medicines Agency (EMA). “I really hope that in a matter of 1 or 2 months from now, this can be approved” in Europe, says EMA’s Marco Cavaleri.
The United Kingdom has been using MVA “off-label” for a few years to vaccinate contacts of imported monkeypox cases. WHO’s Strategic Advisory Group of Experts on Immunization is set to release guidance in the next days that will back MVA, but it will also recommend using earlier vaccines in certain scenarios. Still, Cavaleri says, “If [MVA] is available, clearly that will be the vaccine to start.”
... How well MVA really protects humans from monkeypox is uncertain. The license for MVA in Canada and the United States is based on animal studies, where it was shown to protect macaques and prairie dogs, plus data in humans showing a strong antibody response. A pair of DRC studies vaccinated 1600 health care workers with one of two MVA formulations and found no monkeypox cases in each 2-year study period. But there were no control groups, and one vaccinated health care worker did get monkeypox half a year later. “The truth is, we don’t know the efficacy of any of these monkeypox vaccines,” says Ira Longini, a biostatistician at the University of Florida who is advising WHO.
https://www.science.org/content/art...grows-scientists-debate-best-vaccine-strategy
7 JUN 2022 6:05 PM
BY KAI KUPFERSCHMIDT
... Now, this virus, further weakened and brought to the market by the Danish pharma company Bavarian Nordic, may become key to arresting the largest outbreak of monkeypox ever seen outside Africa, which has already sickened more than 1000 people. It is the only vaccine licensed anywhere for use against monkeypox, although other, riskier smallpox vaccines also appear to offer some protection. The United States, the United Kingdom, Canada, and several other countries have already started to “ring” vaccinate, offering it to contacts of identified monkeypox cases, including health care workers and sexual partners. “MVA will be very important in this outbreak because it is a nonreplicating vaccine, which means it doesn’t have the same side effect profile as some of the other live [virus] vaccines” being considered, says Rosamund Lewis, technical lead on monkeypox at the World Health Organization (WHO).
But what role the vaccine will ultimately play depends on a host of factors: whether those most at risk from infection can be identified and vaccinated, whether the vaccine is as effective as hoped, and whether enough is available to stop the burgeoning outbreak. WHO has so far only backed ring vaccination—MVA is ideally given within 4 days of an exposure but recommended for up to 14 days—but some scientists say it’s too difficult to reach the specific contacts people had. They advocate broader vaccination campaigns in the population most affected so far: men who have sex with men (MSM).
... Bavarian Nordic’s nonreplicating vaccine, marketed as Jynneos in the United States and as Imvanex in Europe, sidesteps some of the risk. So does a vaccinia-based vaccine named LC16m8, licensed for smallpox only in Japan, which also appears to cause fewer side effects. “I believe these are the ones that are going to be used [in the new outbreak] because they have a much-enhanced safety profile,” says Marion Gruber, who headed the U.S. Food and Drug Administration’s vaccine office until October 2021.
Canada and the United States have already licensed MVA for use against monkeypox and Bavarian Nordic is in talks with the European Medicines Agency (EMA). “I really hope that in a matter of 1 or 2 months from now, this can be approved” in Europe, says EMA’s Marco Cavaleri.
The United Kingdom has been using MVA “off-label” for a few years to vaccinate contacts of imported monkeypox cases. WHO’s Strategic Advisory Group of Experts on Immunization is set to release guidance in the next days that will back MVA, but it will also recommend using earlier vaccines in certain scenarios. Still, Cavaleri says, “If [MVA] is available, clearly that will be the vaccine to start.”
... How well MVA really protects humans from monkeypox is uncertain. The license for MVA in Canada and the United States is based on animal studies, where it was shown to protect macaques and prairie dogs, plus data in humans showing a strong antibody response. A pair of DRC studies vaccinated 1600 health care workers with one of two MVA formulations and found no monkeypox cases in each 2-year study period. But there were no control groups, and one vaccinated health care worker did get monkeypox half a year later. “The truth is, we don’t know the efficacy of any of these monkeypox vaccines,” says Ira Longini, a biostatistician at the University of Florida who is advising WHO.
https://www.science.org/content/art...grows-scientists-debate-best-vaccine-strategy
