With a vial of Covid-19 vaccine distributed by Pfizer Biontech it will be possible to vaccinate 6 people instead of 5, starting from the first administrations of the first phase. The goal is to use all the product available in each vial thus avoiding any drug waste. The agreement was reached by AIFA, the Italian Medicines Agency, which suggests that "without prejudice to the need to ensure the administration of the correct quantity of 0.3 ml to each vaccinated subject through the "use of adequate syringes, it is possible to have at least 1 additional dose with respect to the 5 doses declared in the Summary of Product Characteristics (Rcp)".
Six doses instead of five
Each vial of Comirnaty, this is the trade name of the Covid-19 vaccine formulated by the six pharmaceutical companies that currently distribute it, contains six doses but its use in Europe is only authorized for five because to extract all six doses from vials serve special syringes and needles which are not available in all countries. However, in the US, where the vaccine was authorized as a matter of urgency as early as the beginning of December, the use of each full dose obtainable from each vial, hence the sixth, was authorized.
Covid-19 vaccine: correct administration
The dose of vaccine that must be given to each person is 0.3 ml. This dose must be extracted under aseptic conditions and using appropriate precision syringes, from a vial of vaccine containing 2.25 ml, after the intended dilution with 0.9% sodium chloride solution, according to the provisions of Aifa. Any residues from different vials, even if they belong to the same lot number, must not be mixed in any way.
Syringes and additional dose. To extract six doses from a single vial, it is necessary to use syringes and / or needles with low dead volume - specifies the "Ema, the European Medicines Agency - The combination of low volume needle and syringe must have a non dead volume. greater than 35 microliters. If you are using standard syringes and needles, there may not be enough vaccine to extract a sixth dose from a vial. It should be noted that if the amount of vaccine remaining in the vial after the fifth dose is unable to provide a full dose (0.3 ml), the healthcare professional should discard it.
Double administration: vaccine and booster
BNT162b2 (Comirnaty), ie the Covid-19 vaccine, is administered in two doses, usually by injection into the muscle of the upper arm, at least 21 days apart. In jargon: vaccine and booster after three weeks. The term of protection is not yet defined with certainty, but it should be at least 9-12 months. The studies made it possible to evaluate the efficacy of the BNT162b2 (Comirnaty) vaccine on clinically manifest forms of Covid-19: it takes more time to understand if the vaccinated subjects can be infected asymptomatically and infect other people. It is plausible that vaccination protects from infection, but that the vaccinated and their contacts must in any case continue to adopt anti-contagion prevention measures such as distancing, hand hygiene, personal protective equipment such as masks and gloves.
Long-term surveillance and monitoring of the disease and vaccinated people will also show whether vaccine protection is long-lasting or whether additional booster doses are needed, and whether the vaccine effectively prevents a vaccinated person from transmitting the infection.
Side effects of the Covid-19 vaccine
Adverse reactions to the administration of the Covid-19 vaccine do not appear to be serious. In an international study published on 10 December 2020 on the New England Journal of Medicineon two groups of volunteers, one treated with the vaccine and the other with placebo, it was shown that the most common side effect reported by those who received the vaccine was mild to moderate pain confined to the injection area, which however it was resolved in a few days; while less than 1% of the subjects in both groups reported severe pain. There were also few reports of redness or swelling at the injection site.
Systemically, the most common side effects were fatigue and headache (59% and 52%, respectively, after the second dose among younger people; 51% and 39% among older adults), although the same symptoms were also reported by a significant proportion of those who received placebo (23% and 24%, respectively, after the second dose among the youngest; 17% and 14% among the elderly). Among the subjects who received the vaccine, 16% of the young and 11% of the elderly reported high fever (≥38 ° C), which resolved within a few days.
As for serious adverse effects, 64 people who received the vaccine (0.3%) and 6 in the placebo group (<0.1%) reported lymphadenopathy, which resolved within 10 days. Other serious administration-related effects were shoulder problems following the injection, paroxysmal ventricular arrhythmia, right leg paraesthesia.
However, to have the first results of the Covid-19 vaccine we will have to wait several more weeks.
