On May 20, 2022, HAS published a first recommendation for a vaccine strategy against the virus Abekopper (monkey cups). It was subsequently contacted by the Director of Health to provide details on the reactive vaccination strategy for two population groups: first-time recipients and children. To do this, in its opinion of 16 June 2022, HAS has taken into account the definition of cases and contact persons at risk under Public Health France (SPF), the opinion of the National Agency for the Safety of Medicines and Health Products (ANSM). [Lien de l’avis] on the vaccination of persons who had already been vaccinated against smallpox in childhood and the use of the smallpox vaccine by 3e generation in children, WHO recommendations dated 14 June 2022 as well as numerous studies and clinical trials.
One dose for first-vaccination risk contact cases, three if immunocompromised
Preventive vaccination against smallpox was mandatory in France until the 1980s (1979 for primary vaccination, 1984 for boosters). In order to establish, with or without a document justifying vaccination, evidence of previous smallpox vaccination, HAS retains the presence of an indelible waffle jarcharacteristic of persons who have been vaccinated with a vaccine of 1D or 2e generation.
While several studies cited in the HAS opinion have shown a sustained immune response in individuals vaccinated against human smallpox in childhood, three clinical trials have also shown that administration of a dose of Imvanex® in a person who has previously received a primary vaccination with another type of smallpox vaccine, provides a booster effect, even very far from this primary vaccination.
HAS therefore recommends the administration of a single dose of the Imvanex vaccine® for exposed contacts who have received smallpox vaccination with a vaccine of 1D generation before 1980.
In the special case where the contact persons in the risk group are immunocompromised patients, previous vaccination with another smallpox vaccine does not change the vaccination program that was originally recommended in this population, ie. 3 doses of Imvanex®.
Vaccination of minors after exposure should be considered on a case-by-case basis
The number of cases of viral infection Abekopper is developing rapidly in France but does not currently concern children. While smallpox vaccination has long been implemented in infants and young children with first- and second-generation vaccines prior to smallpox eradication, the Imvanex vaccine is® is only allowed in adults.
To deliver its opinion, HAR has analyzed the available studies. Several of them, conducted in African countries, show that children are more likely to develop severe forms of the disease and that mortality is also higher in this population. During the epidemic that hit the United States in 2003, among the 35 laboratory-confirmed cases (of the 71 declared cases), 11 were children aged 6 to 18 years, 2 of whom developed a severe form of the disease.
Moreover, although the Imvanex vaccine® is currently approved for adults only, several studies on other vaccines using the same platform as Imvanex® (that Modified Virus Ankara – VAT), at higher doses than those recommended for Imvanex®, showed good tolerance in children over 4 months. In addition, no side effects were reported after vaccinations – including of children and infants – during the UK outbreak in 2018 and 2019.
HAS also relied on the opinion of ANSM, which points out that the immunogenicity data are insufficient to allow a complete benefit / risk ratio decision; concerning the administration of smallpox vaccines from 3e generation in the pediatric population. However, ANSM assesses this safety data history obtained with vaccines from 1D generation (the vaccine was used from the age of 1 year) as well as the available safety data regarding the “MVA platform” used as a vector for immunization against other pathogens (Ebola virus, malaria and tuberculosis) advocates the use of vaccines from 3e generation, following a case-by-case assessment for each child who underwent reactive post-exposure vaccination.
Based on these various elements, HAS:
- Suggests that reactive vaccination of infants in the risk zone (as defined by SpF) may be considered to protect children who are at risk and possibly more likely to develop severe forms of the disease, especially the most fragile and immunocompromised. However, in the absence of clinical data on the safety of 3. generation vaccines (indirect, reassuring safety data are nevertheless available), HAS recommends that vaccination of persons under the age of 18 be considered on a case-by-case basis, only by specialists and after a rigorous assessment of the benefits and risks of the minor in question. a joint medical decision and with the consent of the parents (or the child’s guardian) and possibly the teenager.
- recommends speeding up the conduct of clinical trials in the pediatric population evaluating the efficacy and safety of third-generation smallpox vaccines with a view to expanding the indication in the pediatric population of EMA.
HAS will adapt this preliminary recommendation as soon as data from clinical trials in the pediatric population are available. and based on new epidemiological and clinical data. It emphasizes the importance of soon having more accurate data on the mode of transmission from human to human for the cases currently identified, epidemic surveillance data and further real data on the efficacy and tolerance of smallpox vaccine.e generation, administered pre-exposure and post-exposure to the virus Abekopperon the prevention of severe forms and on the transmission of the disease in the various subgroups, as well as data on the efficacy and tolerance of a booster dose in persons who have been vaccinated against smallpox in their childhood.
Finally, the cases identified in France concerning men having sex with one or more men (MSM), HAVE insists on need to inform them of the risk of infection during physical contact close together or intimate. She also reminds of the importance to comply with measures to prevent the transfer of virus Abekopper both for the general public and for the nursing staffas recommended by the High Council for Public Health in his opinion of 24 last May.
Find the full statement from HAS