According to recent findings, six doses per vial can only be reliably achieved using low dead volume or low dead space syringes or needles. (Photo: Achraf Hendricks)
Because of the syringes used, vaccinators receive fewer doses per vial than Pfizer says.
First published by GroundUp.
The health department may be overestimating its supply of the Pfizer Covid-19 vaccine used in South Africa.
The vaccines are stored in vials that are supposed to contain six doses. But it is difficult for vaccinators to get more than five doses from a vial.
Here is how the vaccine doses are prepared: Vaccinators add 1.8 milliliters (ml) of normal saline to each bottle. The vial, now containing 2.25 ml of liquid, is gently mixed and doses of 0.3 ml are extracted using measuring needles. If less than 0.3 ml is left in a vial, the vial is discarded.
When using a standard 3 ml needle / syringe combination, approximately 0.08 ml of liquid is left in the so-called dead space of the syringe after the injection, and which is also discarded. In standard 1 ml syringes, this figure is smaller. But there is a class of needles and syringes that minimize this waste called low dead volume (or low dead space) syringes and needles.
When first approved in the United States, Pfizer’s vaccine vials could only hold five doses, and each vial had an overflow serving. Then, on January 6, 2021, the United States Food and Drug Administration, following submissions from Pfizer, granted approval from Pfizer to declare that there are six doses per vial. This result was obtained by Pfizer by experimenting with the use of syringes with low dead volume.
According to the World Health Organization, if six doses per vial are to be obtained, “the low dead volume syringe / needle combination should not have a dead volume greater than 35 microliters. [35µL, or 0.035ml]”.
The dosage dilemma in South Africa
A circular from the South African Department of Health to private healthcare companies said in May that “The price of the Pfizer vaccine from the distributor will be R308.48 per dose. There are 6 doses of vaccine in one vial; therefore the cost per vial is R1850.88 ”
The implication in this paragraph is that we are paying Pfizer per dose, and each vial will produce six doses. So we can assume that this number of six doses per vial is used by the Department of Health in their announcements on how many doses we have received so far and how many we can expect to receive in the coming months.
But this result at six doses is far from assured. Vaccinators who spoke to GroundUp say that it is very difficult to get six doses from one vial with the dosing syringes provided.
Six doses per vial can only be reliably achieved by using syringes or needles with low dead volume or low dead space. GroundUp asked the Department of Health if they counted six doses per vial in their calculations of the total number of doses received. We received no response.
By midnight June 16, 1,494,331 first doses of Pfizer vaccine had been administered, or R461 million vaccine doses. But we pay per bottle. If we assume we only get five doses per vial at the moment, we may have lost up to 300,000 doses, worth R92 million.
The revelation of the six doses surprised syringe and needle manufacturers. According to Bloomberg in February, syringes with low dead space accounted for only 40 million of the 286 million needles and syringes that Becton Dickinson, the world’s largest needle and syringe manufacturer, had been commissioned by the U.S. government to deliver for the program. vaccination. According to Washington postPfizer has now “validated 35 syringe-needle combinations to obtain six doses from the vials,” but only a few manufacturers are capable of producing these types of syringes and needles.
In FebruaryJapan’s Health Minister Norihisa Tamura has downgraded the number of doses available to the country’s population from 144 million to 120 million, after it was revealed that there was a shortage of needles to low volume of dead space in the country. (Unlike South Africa, Japan calculates its total doses based on what can be achieved with the tools at hand.)
In March, the director of the Medical Research Council, Glenda Gray, raised concerns a possible shortage of needles and syringes with low dead volume. In May, the the Wall Street newspaper reported that there was an impending global shortage of low-dead-volume syringes and needles, and that eight US states had reported that they were not receiving enough low-dead volume syringes to extract six doses. the the Wall Street newspaper also reported that an increase in the supply of these syringes “is not expected to occur in the United States until the second half of the year.”
In the United States, unlike South Africa, Pfizer ships its vaccines with appropriate needles and syringes.
If rich countries can’t get these low dead volume syringes, can we?
According to Business for South Africa (B4SA), part of the state tender for the Covid-19 vaccine syringes for (the 1ml and 0.5ml syringes) has been awarded “there is about four weeks ”. According to B4SA, “The contract for 0.3ml syringes has not yet been awarded and is currently on hold due to these syringes awaiting AIAL approval… Pfizer vaccine requires a 0.3ml syringe to optimize its administration. “
Becton Dickinson confirmed with GroundUp that she was one of the successful bidders in this contract and that this order includes a provision for low dead volume syringes.
GroundUp has been trying to get a response from the health service since early June on the state of syringes and needles with low dead volume. Repeated requests were made to Popo Maja, head of communications at the Ministry of Health, as well as Khutso Rabothata, spokesperson for the deputy minister, Dr Joe Phaahla. We received no response. The faulty eTender portal of the National Treasury does not show any information on the contract award for this tender, nor does the official website of the Ministry of Health.
The list of bidders for what appears to be the syringe contract can be viewed here, and the specific condition of the contract here. No mention of low dead volume syringes is made in either document, and no other document is apparently available on this tender or its award.
In a teleconference with the Department of Health on June 18, GroundUp asked the following:
“How many low dead volume syringes and needles are currently available for use in the Covid-19 vaccination program in South Africa, what proportion of vaccination syringes currently in use are low dead volume syringes, and how many have been secured in the coming months? “
In response, Dr Nicolas Crisp replied that “the national tender that has been launched includes 80 million needles and these are either delivered or already in transit. We believe syringe supplies are underway. Pressed further, Crisp said “supply is limited but we expect 54 million 1ml syringes to be delivered by the end of June.” However, at no point did Crisp specify whether these syringes were low dead volume or not.
Standard syringes of 1 ml produce better results than standard 3 ml syringes, as there will be less dose between the plunger and the needle tip after a dose is used. However, it is not clear whether the threshold of 0.035 ml leftover is reached with these needles if they are of the standard variety.
We made a number of inquiries to officials involved in the vaccine rollout over three weeks. If anyone provides us with useful information, we will update it accordingly. DM
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This notice was published: 2021-06-18 13:39:50