key: cord-0312704-1fyt8hp3
authors: Phankavong, P.; Prueksaanantakal, N.; Benjakul, N.; Manomaipiboon, A.
title: Effectiveness of the air-filled technique to reduce the dead space in syringes and needles during ChAdox1-n CoV vaccine administration
date: 2022-05-02
journal: nan
DOI: 10.1101/2022.04.28.22274427
sha: 1f8b04a38d58b705997d5c853eea5e97ce619b7d
doc_id: 312704
cord_uid: 1fyt8hp3

In the current study, we calculated the vaccine volume and amount of dead space in a syringe and needle during ChAdox1-n CoV vaccine administration using the air-filled technique, to reduce dead space in syringe and needle that administer up to 12 doses per vial. The hypothetical situation uses a vial with a similar size as the ChAdox1-n CoV vial. We used distilled water (6.5 ml), to fill the same volume as five vials of ChAdox1-n CoV. When 0.48 ml of distilled water is drawn according to the number on the side of the barrel, an additional 0.10 ml of air can be used in the dead space of the distilled water in the syringe and needle for 60 doses, which can be divided into an average of 0.5 ml dose. ChAdox1-n CoV was administered using a 1-mL syringe and 25G needle to administer ChAdox1-n CoV vaccine into 12 doses using this air-filled technique. The volume of the recipient vaccine will be increase by 20% and save the budget of a low dead space syringe (LDS) .

CC-BY 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted May 2, 2022.

Since December 2019, the SARS-CoV-2 virus epidemic has spread worldwide, leading to 79 the declaration of a pandemic in March 2021 [1] . Several 

A vial of ChAdox1-n.CoV can be divided into ten doses (multiple doses) of 5 ml for ten 91 people. The manufacturers generally overfill the vial to replace the dead space in the syringe and 92 needle in the preparation and injection procedure for ten people. The amount of overfilled vaccine is 93 the same in every brand for multiple dose vials, including Pfizer, which has sufficient vaccines for 94 six people. Therefore, in many countries that have reserved COVID-19 vaccines, the multiple dose 95 type is assigned to use an low dead space (LDS) syringes and needles to reduce the wasted volume 96 that remains in the tip of the syringes and needles [5] . However, the LDS and needle cost is 4 to 10 97 times more than a 1-ml syringe and 25G needle (1 to 1.5-inch length ).Therefore the latter syringes 98 and needle needles are commonly used. Additionally, no manufacturers for LDS and needles are 99 available in Thailand, and they need to be imported from overseas. Moreover, there is a worldwide 100 shortage of vaccines. Therefore, a study about vaccine administration, including the preparation and 101 injection procedure of ChAdox1-n.CoV, to allow the vaccine to be divided to 12 doses per vial . CC-BY 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)

The copyright holder for this preprint this version posted May 2, 2022. ; https://doi.org/10.1101/2022.04.28.22274427 doi: medRxiv preprint 5 102 instead of 10, as limited by the manufacturer, is required. This procedure will help clinics suitably 103 administer the vaccine in the most efficient manner, which will mitigate the supply issues and 104 unavailability of LDS needles in many countries [6].

This research was approved by the Ethics Committee at our hospital, registration no. 108 096/2564.All procedures were performed after written informed consent from all participants.

The research procedure was as follows:

• The test was first performed using distilled water to test the hypothetical situation.

• A vial with a similar size as the ChAdox1-n CoV vial was used. Distilled water of the 112 same volume as a single vial of ChAdox1-n CoV(6.5 ml) was filled in the vial. Thailand (NIMT) as described below.

Step 1: 60 sets of 1-ml syringe and 25G needle were weighed and recorded, with a length of 117 1 inch needle , and the weighted average was calculated.

Step 2: 0.45 ml water with 0.1 ml air was aspirated, resulting in < 0.5 ml water being 119 ejected. from the.syringe.

Step 3: 0.48 ml of distilled water and an additional 0.10 ml of air was drawn into the syringe 121 to reduce the dead space in the syringe and needle. The amount of the water appeared to be slightly 122 more than 0.5 ml. Thereafter, the weight of 60 sets of syringe and needle were recorded and 123 weighted average was calculated.

Step 4: 0.5 ml of distilled water from the barrel was discarded, syringe and needle were 125 weighed, the weight recorded,, and the weighted average calculated.

. CC-BY 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted May 2, 2022. ; https://doi.org/10.1101/2022.04.28.22274427 doi: medRxiv preprint 6 126 • The experiment using the same procedures was repeated until 12 doses of distilled water 127 were obtained per vial, for which the amount in every dose was ≥ 0.5 ml.

• The second stage involved using ChAdox1-n CoV in the real situation in the same way as 129 in the hypothetical situation as described below.

Step 1: Sixty sets of 1-ml syringes and 25G needles, with a length of 1 inch needle, were 131 weighed, the weight recorded, and the weighted average calculated. Five vials of vaccine were used.

Because a vial can be divided into 12 doses, five vials would comprise 60 doses.

Step 2: The vaccine was prepared by stabbing the needle in the vaccine vial and drawing in 0.48 134 ml of vaccine and an additional 0.10 ml of air to reduce the dead space in the syringe and needle.

The amount of the vaccine would appear to be equal to or slightly more than 0.5 ml. Thereafter, the 136 60 syringe and needle sets were weighed, the weight recorded, and the weighted average calculated.

Step 3: The vaccine was injected to the muscle of the vaccine recipient following the 

In the experiment using 6.5 ml of the distilled water in the vial, having the same size as the 

All the authors declare that they have no competing interests.

. CC-BY 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. 

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. CC-BY 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. . CC-BY 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted May 2, 2022. ; https://doi.org/10.1101/2022.04.28.22274427 doi: medRxiv preprint