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Saturday, April 3, 2021

Wich Vaccine is Better ? What Vaccine Should I Take ?

 


A study Comparing the Covid-19 vaccines developed by Pfizer, Moderna, and Johnson & Johnson

Vaccine types

The Pfizer and Moderna vaccines are made using messenger RNA , or mRNA, a technology that delivers a touch of ordering to cells — in effect, a recipe to form the surface protein (known as spike) on the SARS-2 virus. The proteins made with the mRNA instructions activate the system , teaching it to ascertain the spike protein as foreign and develop antibodies and other immunity weapons with which to fight it.

The J&J vaccine uses a special approach to instruct human cells to form the SARS-2 spike protein, which then triggers an immune reaction . it's what’s referred to as a viral vectored vaccine. A harmless adenovirus — from an outsized family of viruses, a number of which cause common colds — has been engineered to hold the ordering for the SARS-2 spike protein. Once the adenovirus enters cells, they use that code to form spike proteins. J&J employed this same approach to form an Ebola vaccine that has been authorized to be used by the ecu Medicines Agency.

Target population

The Pfizer vaccine has been authorized to be used for people aged 16 and older. Moderna’s has been cleared to be used in people 18 and older, though the corporate is now testing its vaccine in 12- to 17-year-olds. J&J’s vaccine has been tested in people 18 and older, and that’s who it had been authorized for. Until testing in children and younger teens is conducted, this vaccine won’t be available to be used anyone under 18 years old either.

Vaccine efficacy

The Pfizer and Moderna vaccines have shown astonishing — and essentially equivalent — degrees of efficacy, a minimum of within the early stages after vaccination.

The Pfizer vaccine showed efficacy of 95% at preventing symptomatic Covid infection after two doses. The vaccine seemed to be more or less equally protective across age groups and racial and ethnic groups.

The Moderna vaccine was 94.1% effective at preventing symptomatic Covid-19 after the second dose. The vaccine’s efficacy seemed to be slightly lower in people 65 and older, but during a presentation to the Food and Drug Administration’s advisory committee in December, the corporate explained that the numbers could are influenced by the very fact there have been few cases therein age bracket within the trial. The vaccine seemed to be equally effective across different ethnic and racial groups.

But comparing the efficacy of these vaccines to the efficacy of Johnson & Johnson’s is challenging due to differences within the designs of the Phase 3 clinical tests — essentially the trials were testing for various outcomes. Pfizer’s and Moderna’s trials both tested for any symptomatic Covid infection. Pfizer started counting cases from seven days after receipt of the second dose of vaccine, while Moderna waited until day 14 to start out counting cases.


J&J, against this , sought to work out whether one dose of its vaccine protected against moderate to severe Covid illness — defined as a mixture of a positive test and a minimum of one symptom like shortness of breath, beginning from 14 or 28 days after the only shot. (The company collected data for both.)


Because of the difference within the trials, making direct comparisons may be a bit like comparing apples and oranges. Additionally, Pfizer and Moderna’s vaccines were tested before the emergence of troubling new variants in Britain, South Africa , and Brazil. It’s not entirely clear how well they're going to work against these mutated viruses.


The J&J vaccine was still being tested when the variants were making the rounds. Much of the info generated within the South Africa n arm of the J&J trial involved people that were infected with the variant first seen in South Africa, called B.1.351.

The J&J one-dose vaccine was shown to be 66% protective against moderate to severe Covid infections overall from 28 days after injection, though there was variability supported geographic locations. The vaccine was 72% protective within the us , 66% protective in South America, and 57% protective in South Africa .


But the vaccine was shown to be 85% protective against severe disease, with no differences across the eight countries or three regions within the study, nor across age groups among trial participants. And there have been no hospitalizations or deaths within the vaccine arm of the trial after the 28-day period during which immunity developed.

It’s not yet known if any of those vaccines prevent asymptomatic infection with the SARS-CoV-2 virus. neither is it known if vaccinated people can transmit the virus if they are doing become infected but don’t show symptoms.

Number of doses/amounts of vaccine per dose

Both the Moderna and therefore the Pfizer vaccines require two shots: a priming dose, followed by a booster . The interval between Moderna doses is 28 days; for the Pfizer vaccine, it’s 21 days.

Each dose of Pfizer’s contains 30 micrograms of vaccine. Moderna went with a way larger dose of vaccine, 100 micrograms. It means the corporate is employing a little quite 3 times the maximum amount vaccine per person as Pfizer is. And yet, they aren’t recuperating results. The government’s vaccine development program, formerly called Operation Warp Speed, has asked Moderna to check if it could lower the dosage of its vaccine without eroding the vaccine’s protection.

The J&J vaccine is, as mentioned, a single-dose vaccine. the corporate is additionally testing a two-dose regimen, with the 2 shots given eight weeks apart. The results from that 30,000-person trial aren’t expected until sometime in May. the only dose contains more antigen than the individual doses within the two-dose regimen.J&J is additionally testing what happens to antibody responses when an individual who received the only dose regimen receives alittle booster quite bit later, Johan Van Hoof, director of Janssen Vaccines revealed recently. Van Hoof didn’t say how long the interval is between the only shot and therefore the small booster, nor did he say when J&J expects results from that study.

Side-effect profile

in the vernacular of vaccinology, shots that trigger a variety of transient side effects during a lot of recipients are referred to as reactogenic.

All of those vaccines — actually , most if not all the Covid-19 vaccines that have reported data thus far — fall under the reactogenic category. The Advisory Committee on Immunization Practices, an expert panel that helps the Centers for Disease Control and Prevention set vaccination policies, advised hospitals early within the rollout that they could want to stagger vaccinations among employees just in case some feel too unwell to figure the day after being vaccinated.

The most common side effects are injection site pain, fatigue, headache, muscle pain, and joint pain. Some people within the clinical trials have reported fever. With the Pfizer and Moderna vaccines, side effects are more common after the second dose. Younger adults, who have more robust immune systems, reported more side effects than older adults.

To be clear: These side effects are a symbol of an system kicking into gear. they are doing not signal that the vaccine is unsafe. so far there are not any serious, long-term side effects related to receipt of those vaccines, which can be closely monitored as their use expands.

There are reports of severe allergies to the mRNA vaccines. Both the Pfizer and Moderna vaccines appear, on rare occasions, to trigger anaphylaxis, a severe and potentially life-threatening reaction. people that develop anaphylaxis must be treated with epinephrine — the drug in EpiPens — and should got to be hospitalized to make sure their airways remain open. The CDC says people should be monitored for quarter-hour after getting a Covid-19 shot, and half-hour if they need a history of severe allergies.

J&J recently revealed that one case of anaphylaxis has been reported in someone who received its vaccine.

It will take time to return up with a firm estimate of how frequently this side effect occurs. the foremost recent data from the CDC suggest that anaphylaxis occurs at a rate of about 2.5 cases per a million doses given of the Moderna vaccine, and 4.7 cases per million doses of the Pfizer. Many of the people that have developed anaphylaxis have a history of severe allergies and a few have had previous episodes of anaphylaxis.

Safety for those that are pregnant or lactating

None of the vaccines has been tested in these two groups, although Pfizer recently began a Phase 2/3 trial to check the security and efficacy of its vaccine during pregnancy. Van Hoof said J&J will begin an identical trial in late March or early April.

Moderna has completed animal studies the FDA demanded of manufacturers; these studies search for evidence that the vaccine might harm the pregnancy or the developing fetus. the corporate said it saw no such signals.

The CDC recommends until those studies are conducted, the selection of whether to urge vaccinated should rest with the one that is pregnant or lactating. this is often a more permissive stance than has been taken in some countries, which have said people that are pregnant shouldn't be vaccinated with these vaccines.Storage requirements

The mRNA vaccines require an elaborate cold chain, the term wont to describe the conditions under which vaccines must be stored during distribution and once they are within the doctors’ offices, pharmacies, or public health clinics where they’ll be administered.

The J&J shot doesn't , which suggests this vaccine are often given easily anywhere — in doctors’ offices, pharmacies, mass vaccination sites, public health clinics — once supplies are adequate. It are often stored for a minimum of three months at the temperature of a daily refrigerator.

Of the mRNA vaccines, Pfizer’s was originally the harder to use. It had to be shipped and stored in ultra-cold freezers — ones that would keep the vials at -94 degrees Fahrenheit. But recently, the FDA announced that the vaccine are often shipped and stored — for a two-week period only — at temperatures of normal pharmacy freezers, between -13 and 5 degrees Fahrenheit. that ought to make the ultimate stage of the vaccine’s journey from production plant to syringe able to plunge into an arm somewhat easier.

Moderna’s must be shipped at -4 degrees Fahrenheit, which is within the temperature of a daily refrigerator freezer.

After thawing, a vial of the Pfizer vaccine must be used within five days; Moderna’s is stable at fridge temperature for 30 days and at temperature for 12 hours. J&J’s vaccine are often stored at temperature — to not exceed 77 degrees Fahrenheit — for 12 hours when the vial hasn’t yet been punctured. After the primary dose is withdrawn, the vial are often stored during a fridge for 6 hours or at temperature for 2 hours.

Minimum order 

The cold-chain requirement isn't the sole challenging aspect of the Pfizer vaccine. The minimum amount of vaccine a location can order is 1,170 doses. an outsized teaching hospital might need several of these . But there are many places across the country that might not have needed 1,000 doses to vaccinate the people eligible for vaccination within the early stages of the rollout, when only selected groups of individuals were eligible to urge vaccine. As states enter vaccinating larger segments of the population, this massive minimum order size subsided of an obstacle .

The Moderna vaccine’s minimum order is 140 doses, a way more manageable number.

STAT has asked J&J several times what its minimum order will be; the corporate has not yet disclosed that information.

The Pfizer vaccine is shipped in six-dose vials. Moderna’s vaccine comes in 14-dose vials. J&J’s vaccine is packaged in five-dose vials.

Durability of protection
Figuring out how long the protection provided by any of those vaccines will last will take time. It’s getting to involve periodic blood draws from some volunteers to ascertain what their antibody levels appear as if , though a decline in antibody levels doesn’t necessarily equate to loss of protection.

But an outsized a part of this work will involve expecting reports that folks who were immunized are beginning to contract Covid in larger numbers, a development that might probably cause recommendations to offer people booster shots at some yet-to-be-determined interval.