COVID-19 Aşıları

COVID-19 aşılarının üretiminden aşılamaya yolculuğu

Küresel COVID-19 aşılarının önde gelen üreticileri ortaya çıktı ve ilk enjeksiyonlar İngiltere, Amerika
Birleşik Devletleri ve başka yerlerde uygulanmaya başlandı. Ancak bu çok beklenen aşıları dünya çapında
dağıtmanın yolu, derin dondurmalar, dikkatli zamanlama, uçaklar, trenler, kamyonlar derken, beklenenden
zorlu geçecek.

Aşağıda, son aşama denemelerinde yeni koronavirüs enfeksiyonlarının önlenmesinde etkili olan, önde gelen
üç deneysel aşının yolculuklarına göz atacağız. İlki Pfizer Inc ve BioNTech SE’den, ikincisi Moderna Inc’den -ABD Ulusal Alerji ve Bulaşıcı Hastalıklar Enstitüsü ile birlikte ve üçüncüsü AstraZeneca ve Oxford Üniversitesi’nden.

Pfizer-BioNTech

Moderna

AstraZeneca

Aşının kaynağı

Bazı aşılar gelecek vaat eden teknolojilere güvenirken, diğerleri geçmişte başarılı olduğu kanıtlanmış yaklaşımlara güveniyor.

Yeni mRNA teknolojisi

Bu aşıların her ikisi de, vücut hücrelerine yeni koronavirüsteki başak proteinlere benzer proteinler yapma talimatı vermek için kimyasal bir haberci kullanıyor.

Değiştirilmiş taşıyıcı virüs

Zayıflamış bir şempanze adenovirüsü, koronavirüs başak proteinlerinin genetik dizisini içerecek şekilde değiştirildi. .

Aşı şişeleri

Sıcaklığa duyarlı aşıların etkili bir şekilde depolanması için kritik olan aşı şişeleri, hasar görürse ilaçları kullanılamaz hale getirebilir.

Moderna aşısı

Bir şişede 10 doz bulunur ve her bir kişi 28 gün arayla verilen 2 doza ihtiyaç duyacaktır.

AstraZeneca aşısı

Bir şişede 8-10 doz bulunur ve her bir kişi 28 gün arayla verilen 2 doza ihtiyaç duyacaktır.

Pfizer aşısı

Bir şişede 5 doz bulunur ve her bir kişi 21 gün arayla verilen 2 doza ihtiyaç duyacaktır.

Soğuk zincir

Aşıları stabil tutmak için soğuk-sıcaklıklarda dağıtım ve saklama süreci.

Yerleşik soğuk zincir

Most pharmaceutical distribution companies are able to store and move the two vaccines.

Özel üretilmiş ultra-soğuk kaplar

Çoğu ilaç dağıtım şirketi, iki aşıyı depolayabilir ve taşıyabilir.

Container with dry ice sits above the vaccines.

Each tray can fit 195 vials.

1 to 5 trays fit in the inner payload carton and once closed, dry ice fills the sides and
spaces.

Medium thermal shipper is about the size of a carry-on suitcase.

Production

Within the company

Pfizer and BioNTech plan to make raw materials and produce the vaccine themselves.

Contracting services

Swiss contract drug manufacturer Lonza will be producing much of the Moderna vaccine along
with other contractors and Moderna itself.

Using global infrastructure

Able to produce in existing sites, AstraZeneca has signed supply and
manufacturing deals around the world.

Planes, trains and trucks

Typically, airlines use containers with cooling materials, such as dry ice, to transport pharmaceutical
products, but some don’t have temperature controls, making products susceptible to unforeseen events
such as flight delays.

Airlines are now considering options ranging from a large plug-in freezer, which can cost about as much
as a small car, to a multi-layered canister that uses liquid nitrogen to ship vaccines requiring a deep
freeze.

Some trucks will be packed with dry ice and others will be refrigerated. Some will have no temperature
controls and will rely solely on the cooling stability of the vaccine transport coolers.

Unlike Pfizer’s vaccine which needs to be shipped and stored at -70 Celsius
(-94 F), the Moderna and AstraZeneca
vaccines do not require specialized ultra-cold freezers or vast quantities of dry ice, making it easier
to supply rural and remote areas. UNICEF is working with manufacturers and other partners to procure
COVID-19 vaccines for poorer countries, as well as help them with freight, logistics and storage.

The U.N. children’s agency, which has experience delivering medicines to all corners of the world, calls
the “cold chain” a complex undertaking that requires precise coordination in temperature-controlled
environments to prevent a vaccine from losing its potency. “From storage facilities down to the village
level, health workers carry vaccines in cold boxes and vaccine carriers, traveling by car, motorcycle,
bicycle, donkey, camel or on foot to immunize every last child, even in the most remote of villages,”,
UNICEF said on its website.

Awaiting vaccination

As vaccines travel from the manufacturer to the clinics, shipments will cross time zones and different
environments. But the integrity of the vaccine relies on stable, consistent temperatures.

If the correct cold chain temperatures are maintained, all three vaccines will have a shelf life of about
six months. But vaccines are sensitive to temperature variations and once stability is compromised, it
cannot be recovered. Temperatures should be monitored throughout the vaccine’s shelf life.

Vaccines can be removed from their long-term, temperature-controlled environments anytime before the
six-month expiry date. But once refrigerated or in room temperature, the time of stability becomes
shorter.

°C

°F

40

100

Body temperature

Vaccines

stored at

5°C

AstraZeneca

Out of storage

2 to 8°C for at least 6 months

AstraZeneca vaccine can be administered in existing healthcare settings —
stored, transported and handled at normal refrigerated conditions.

2 to 8°C

32°F

0°C

6 hours at room temperature

After first opening the vial, the AstraZeneca vaccine
should be used within 6 hours.

After dilution, the Pfizer vaccine should be used
immediately and within 6 hours.

2-8°C for 5 days

Once out of the thermal shippers,

Pfizer doses can be refrigerated.

2° to 8°C for up to 30 days

Moderna vaccine can be refrigerated for a month within the six-month shelf
life.

Vaccines often need to be transported long distances, while maintaining
stable temperatures along every step of the way.

Frozen desserts

-20°C

Moderna

Up to 6 months at -20°C

For shipping and long-term storage, Moderna expects the vaccine will be
stable in most home or medical freezer temperatures.

-20°C ± 5°C

12 hours at room temperature

Once the first dose has been taken, the other doses in the vial should be
administered within 6 hours.

-40°F

-40°C

-70°C for up to 10 days

Pfizer thermal shippers stabilise ultra cold temperatures with dry ice.

After 10 days, the shippers need to be refilled with 23kg
of dry ice and then refilled again every 5 days.

After 15 additional days

Pfizer doses need to be removed from the thermal shippers and either stored
short term in medical refrigerators or long term in ultra-low freezers.

Up to 6 months at -70°C

Stored in ultra-low-temperature freezers, which are commercially available
and can extend the shelf life of the Pfizer vaccine.

South Pole average

winter temperature

-70°C

Pfizer-BioNTech

-70°C ± 10°C

1 month

3 months

End of shelf life

2 months

4 months

5 months

Cold chain begins

Maximum duration in a storage condition

-100

-150

Into the arms of the people

Once out of storage, the coronavirus vaccines all have different requirements for prepping. The AstraZeneca vaccine can be administered straight from the vial. The Moderna dose needs a gentle swirl after the vial is thawed. And the Pfizer vaccine, fresh out of a deep freeze, will require dilution and repeated
inversion, but do not shake.

The attention and consideration necessary for the Pfizer vaccine could require specialist skills that may
not be available in all corners of the globe. Timings and protocol will need to be followed closely.

Storage at vaccination facilities

Specialist storage

Stability of the Pfizer vaccine requires specialist ultra-cold freezers and storage.

Established cold chain

Moderna and AstraZeneca vaccines can be stored in existing medical freezers and
refrigerators.

Vaccination prep

Frozen vaccines must be thawed and brought up to room temperature before
being used.

The vials should be inspected for any discolouration or visible particles.

Onsite work

Once thawed, the Pfizer vaccine must be diluted with a saline solution in the vial and be
gently inverted 10 times.

Ready to go from the vial

Moderna and AstraZeneca vaccines do not require onsite dilution or special handling.

Injection

Syringes and needles of appropriate gauge and length are required for
people of different age, gender and weight.

Shot in the arm

Vaccines are administered by intramuscular injection into the upper arm.

Second dose

The booster shot helps in bolstering the immune response.

Pfizer vaccine

3 weeks later

AstraZeneca vaccine

4 weeks later

AstraZeneca is considering combining its vaccine with others including Sputnik V, developed
by Russia’s Gamaleya Institute, to see if it can boost efficacy.

Moderna vaccine

4 weeks later

95% effective

94.1% effective

70% effective

Efficacy

The percent reduction in the number of infections in the vaccinated group
compared to the unvaccinated group.

Efficacy in adults over 65 years, who are at particular risk from the virus, was over 94%

With no serious safety concerns and a 100% success rate in preventing severe cases

62% effective with two full doses, but it was 90% effective in a small group of trial
subjects who received first a half dose, then a full dose.

Generally, a vaccine’s real-world effectiveness tends to be slightly lower than its efficacy in clinical
trials.

In the real world, there are multiple, unpredictable factors, including how many, or few, people adhere
to the optimum dosing schedule and timetable; how individuals’ immune systems respond; whether the
vaccine was stored at the correct temperature; whether people know, or don’t know, if they have been
exposed before.

It is also not known how long a vaccine will protect someone from the SARS-CoV-2 coronavirus. BioNTech
Chief Executive Officer Ugur Sahin has said he is optimistic the immunization effect of the vaccine
would last for a year.Experts say that it is likely we will have to live alongside the virus.

The evidence suggests that the COVID-19 vaccines developed by Pfizer-BioNtech, Moderna and AstraZeneca will help stop people developing the disease. Only
AstraZeneca’s data, so far, shows signs that its vaccine may also help prevent transmission of the
virus.

Sources

Pfizer; Moderna; AstraZeneca; World Health Organization; U.S. Centers for Disease Control and Prevention;
Public Health England, UK government; Reuters

By Michael Ovaska and Prasanta Kumar Dutta

Edited by

Simon Scarr and Tiffany Wu