It is administered to those who have had close contact with those who have become infected and contracted monkeypox. Everyone wants theImvanex. The UK Health Safety Agency (Ukhsa) has purchased over 20,000 doses and considers it “a safe vaccine against smallpox.” The Imvanex of Denmark’s Bavarian Nordic is regarded by the British as “part of the rapid response to the increase in monkeypox cases.”
This vaccine, explains the health authority, is offered to “identified close contacts of people diagnosed with monkeypox, to reduce the risk of symptomatic infections and serious illnesses ». The smallpox vaccine of Bavarian Nordic – explains the Scandinavian company on its website – is approved in the United States and Canada under the names of Jynneos * and Imvamune * respectively. In both countries the product is suitable for both human and monkey smallpox. The vaccine is also approved in Europe as Imvanex * and the indication is for human smallpox only, but the product has previously been provided for off-label use in response to monkeypox cases.
As for the European Union, the Spanish Minister of Health, Carolina Darias, announced that the EU will purchase vaccines and antivirals to be made available to member countries. The vaccine that will be bought will be Imvanex. The purchase will be managed by the Authority for the preparation and response to health emergencies (Hera), she specified.
How is it used?
Imvanex is administered by injection, reads the website of the European Agency Ema. People who have not previously been vaccinated against smallpox should be given two doses of 0.5 ml, with the second dose given at least 28 days after the first. If a booster dose is required for those who have been vaccinated against smallpox in the past, a single 0.5 ml dose should be given, except for patients with a weakened immune system (the body’s natural defenses) who they should receive two booster doses, with the second dose given at least 28 days after the first. The vaccine can only be obtained with a prescription.
How does it work?
Vaccines work by “teaching” the immune system how to defend itself against a disease. When a person receives the vaccine, the immune system recognizes the virus contained in the vaccine as ‘foreign’ and makes antibodies against it. When the person comes into contact with this virus or a similar virus again, these antibodies, together with other components of the immune system, will be able to kill the viruses and protect against disease. Imvanex contains a modified form of the virus (called Vaccinia virus Ankara – MVA) which does not cause disease in humans and cannot replicate in human cells. Given its similarity to the smallpox virus, antibodies produced against this virus are expected to protect against monkeypox as well. MVA vaccines have been effective in the smallpox eradication campaign.
What benefits are proven?
The European Medicines Agency replies that studies have shown that Imvanex is effective in triggering the production of antibodies to a level that provides protection against smallpox. Five main studies were conducted. The studies involved over 2,000 adults, including patients with HIV and atopic dermatitis (an itchy skin condition caused by an overactive immune system) and people who had been vaccinated against smallpox in the past. Two of the studies specifically looked at Imvanex’s effectiveness as a booster. A subsequent study in 433 people who had not previously been vaccinated found that the level of protective antibodies after vaccination with Imvanex was at least as high as that of a conventional smallpox vaccine. It is not yet known how long the protection will last.
What are the risks?
The most common side effects of Imvanex (which may affect more than 1 in 10 people) are headache, nausea, myalgia (muscle pain), tiredness and reactions at the injection site (pain, redness, swelling, hardening and itching). Imvanex must not be used in patients who are hypersensitive (allergic) to the active substance or to any of the substances present in trace amounts, such as chicken proteins, benzonase and gentamicin. For the full list of side effects and limitations, see the package leaflet.