Flu spray vaccines

The Lombardy Region announced to have reached an agreement with pediatricians to strengthen the flu vaccination campaign among children up to 6 years. The initiative will start in mid-November and will involve the use of spray vaccines, usually not used in Italy compared to the more traditional vaccines to be administered via an injection.

Several details on the program are not yet clear and the start in November is considered late, given that the Ministry of Health has been recommending anticipate influenza vaccination campaigns, given the concomitance with the ongoing coronavirus pandemic. At least in the initial phase, the symptoms of COVID-19 can be confused with those of the flu, complicating diagnoses. The flu vaccine helps reduce cases of flu, which can lead to severe symptoms in at-risk individuals, relieving the workload for hospitals, which could find themselves in trouble again with the coronavirus as they did in the first half of the year.

Classic vaccine and spray
Most of the flu vaccines it is given through an intramuscular injection. Inside, the vaccine contains an inactivated version of the virus (usually between two and four variants, which are estimated to be those in circulation in each flu season) capable of eliciting an immune response, but without running the risk of getting sick. This system teaches the immune system to recognize flu viruses, so it can deal with them, and prevent them from starting an infection that could then lead to illness.

In some countries, a variant of the classic vaccine called LAIV has been available for some time (Live attenuated influenza vaccine). As the name suggests, it contains still alive and active influenza viruses, but treated in such a way that they are less aggressive than the version circulating among the population. LAIV is administered via a nasal spray and is then taken by inhalation.

The flu strains contained in the LAIV are treated in such a way that they can resist the temperature of the nasal mucosa by replicating within them, without affecting the lower respiratory tract. This reduces the risk that attenuated viruses can sneak too deep, causing infections that could be risky.

The use of the LAIV
So far in Italy the experiences with the LAIV have been extremely limited, and the Ministry of Health itself reported until recently that: “The vaccine is not currently available in Italy”. According to what declared by the Lombardy Welfare Councilor, Giulio Gallera, by mid-November the region will receive about half a million doses that will be used for vaccinations (on a voluntary basis by parents) of children. According to the promoters of the initiative, administration should be faster and more practical, less traumatic for children and therefore better seen by parents. However, several details are not yet clear.

The use of LAIV is allowed in Europe and in recent times it has been the basis of some vaccination campaigns against influenza in the pediatric sector. Programs similar to the one Lombardy is working on have been made in the UK and Finland, where spray vaccines were offered to children in the 2-11 and 2-3 year age groups respectively.

The use of the LAIV is not recommended under 2 years of age because it can cause temporary respiratory problems. Gallera spoke of an “organizational plan for the influenza vaccination of children aged between six months and six years”, this implies that up to 2 years the vaccine to be injected will be used, leaving the other to the older children.

Administration of the LAIV usually requires two doses, to be given one month apart, but in some countries the use of a single dose has been tried with satisfactory results. The Lombardy Regional Prevention Department will have to establish whether one dose is sufficient or whether a booster should also be performed.

Effectiveness
Beyond the uncertainties about Lombardy’s programs, doubts had been raised in the past about the effectiveness of LAIV compared to the traditional vaccine. The US health authorities (CDC) in 2016 had not recommended the use of the LAIV in the flu season of that year due to its lower efficacy, which emerged in the previous three flu seasons. Subsequently, an analysis conducted on the administration in children he noted that the LAIV had led to results below expectations in some age groups.

To date, it is still not completely clear why the LAIV has proved less reliable in some flu seasons. At the beginning of 2018, however, the health authorities returned to recommend the use of the spray vaccine, removing the indications that indicated that the use of the traditional one as preferable following new analyzes on its effectiveness.

Inquire about
Getting vaccinated against the flu is always important for individuals at risk, such as the elderly and those with other diseases, and could be even more so this year due to the pandemic. The Ministry of Health recommended that the vaccination campaign be brought forward and that the vaccine be offered free of charge to larger sections of the population. Following these guidelines, each Region, which is responsible for health management, has launched its own vaccination programs. For information, you can contact the ASL or your doctor.

–