Covid-19 Vaccine Ready?

→ Article updated 2-10-2021

The public is advised to brace for some stronger-than-usual side effects from the Covid-19 shots. More than say a typical flu shot and to possibly take a day or two off from work to recover.

♦ On November 9^th, Pfizer and BioNTech announced that they had jointly developed an effective vaccine for Covid-19.

On December 11^th, the FDA issued an Emergency Use Authorizations (EUA) for the Pfizer-BioNTech vaccine for use in individuals 16 years of age and older.

Distribution of Pfizer's vaccine began Saturday, December 12^th, with shots expected to be given on Monday.

Pfizer’s vaccine requires two doses, given 21 days apart to be effective.

♦ On November 16^th, Moderna claimed their vaccine showed a high effective level.

On December 18^th, the FDA issued an EUA for the Moderna vaccine for use in individuals 18 years of age and older.

Distribution of Moderna's vaccine began Saturday, December 19^th, with shots expected to be given as soon as Monday.

Moderna’s vaccine requires two doses, given 28 days apart to be effective.

♦ On January 29^th, 2021, Johnson & Johnson announced that in a large-scale trial (44,000 people) their single-dose vaccine showed some mixed results. The vaccine's level of protection against moderate to severe COVID-19 was 72% in the U.S., 66% in Latin America and drops to 57% in South Africa.

These numbers may seem underwhelming but by comparison to the annual flu shot, which ranges from 40 - 60% effective, the J & J shot can still play a major role in stopping the spread of COVID-19.

• On February 4^th, 2021, Johnson & Johnson applied to the FDA for Emergency Use Authorization (EUA). If approved, the vaccine could be ready for use in the U.S. by the end of March.

Johnson & Johnson's vaccine requires a single dose.

♦ On November 23^rd, AstraZeneca announced that their vaccine was showing good results. But doubts have since arisen about how they conducted their trials.

The AstraZeneca vaccine has NOT been approved by the FDA. There was some uncertainty over the test results and this has clouded its prospects in the U.S. for a while. A U.S. study of AstraZeneca’s vaccine involving some 30,000 volunteers is in the works and should produce data by late January.

• AstraZenica may not be able to apply to the FDA for EUA until the spring of 2021.

The AstraZeneca vaccine received approval in the U.K. on December 30^th, 2020.

• February 9^th, 2021, a study from South Africa suggests that the AstraZenica vaccine provided "substantially reduced" protection against mild to moderate cases of the South African variant of the virus. It is thought the AstraZenica vaccine will still prevent more serious cases of the COVID-19.

AstraZeneca’s vaccine requires two doses, given four weeks apart to be effective.

If time were not of the essence, it would make sense to wait for longer-term data on all the new vaccines. But in the face of a pandemic, that is not sensible.

That is why there are regulations governing emergency use along with close monitoring of these new vaccines.

The vaccines will be restricted to those who need them the most—doctors, nurses and other healthcare workers and also the elderly.

Close monitoring for side effects will be necessary as they are to be expected as a larger portion of the population receives these vaccines. But we can also expect that as more data is accumulated over the first months of next year, restrictions are likely to be loosened.

Who will take the shot?

At the moment, surveys suggest that anywhere between 20% and 60% of Americans may refuse to be vaccinated. Compare this to the U.K. where polls say 79% of the country's inhabitants intend to get vaccinated.

In one survey only a third of nurses in the U.S. said they would voluntarily get vaccinated.

Some people are worried that the vaccines may not be safe, suspicious that corners may have been cut in the rush to develop them so quickly.

Others have seen various kinds of alarming misinformation.

Muddled messages from various political leaders have also done their share of harm.

Similar strategy

All three vaccines use the same strategy: to introduce into the human body instructions for the “spike” protein on the outside of SARS-CoV-2, the virus that causes Covid-19.

• The vaccines from Pfizer and Moderna introduce instructions by using molecules known as messenger RNA (mRNA) enclosed inside small fatty particles.

Unlike the Pfizer and Moderna vaccines, which store the instructions in single-stranded RNA, the AstraZeneca vaccine uses double-stranded DNA.

• AstraZeneca’s vaccine incorporates the instructions into the genetic material of a harmless cold virus, or adenovirus that causes infections in chimpanzees.

AstraZeneca’s approach is regarded as particularly interesting, because this is the first successful example of what researchers hope will be a new class of drugs that work by feeding cells instructions to make therapeutic proteins in place; the protein for the “spike.”

♦ The AstraZeneca vaccine is more rugged than the mRNA vaccines from Pfizer and Moderna. DNA is not as fragile as RNA, and the adenovirus’s tough protein coat helps protect the genetic material inside. As a result, the AstraZeneca vaccine doesn’t have to stay frozen. The vaccine is expected to last for at least six months when refrigerated at 38–46°F (2–8°C).

• During the clinical trial of the vaccine, the researchers unwittingly gave some volunteers only half a dose.

Surprisingly, the vaccine combination in which the first dose was only half strength was 90% effective at preventing Covid-19 in the clinical trial.

♦ If the AstraZeneca vaccine proves successful, it also would be easier and cheaper to distribute than the Pfizer vaccine. And because this vaccine is also a fraction of the price of the others, it might end up being the most popular choice.

Like Pfizer and Moderna, the AstraZeneca inoculation is administered in two shots.

The researchers from AstraZeneca and Oxford also say that their vaccine may reduce passage of the virus between people — a property not yet established for either of the other two vaccines.

An ideal vaccine needs to break the chain of transmission, as well as stopping recipients from falling ill, so AstraZeneca’s claim is important.

Pfizer vs Moderna

Compared to Pfizer, Moderna’s vaccine far easier and cheaper to distribute, although the cost of the Moderna vaccine itself is higher.

Pfizer’s vaccine must be stored at -70°C, which is the temperature in ultra-freezers rarely found outside research laboratories and big medical facilities. To deal with that, Pfizer will be distributing the vaccine in “thermal shippers.” special containers packed with dry ice designed to hold between about 1,000 and 5,000 doses. The dry ice must be replenished regularly, the container can be opened only twice a day and, once taken out, the vaccine lasts in a regular refrigerator for only five days. When ready to administer, it must be diluted with saline, which is not a common step for vaccines.

♦ People handling the Pfizer vaccine will need extensive training. Because of all these involved steps, a fair amount of the first supplies of Pfizer’s vaccine may end up being spoiled.

As expected, there was some confusion with the initial Pfizer rollout. Pharmacists discovered that, after thawing and mixing the contents with a diluent, each vial contained enough vaccine for six doses.

Pfizer was not available to confirm if the sixth dose was safe to give. This was odd since this same issue came to light in the U.K. where Pfizer had earlier been distributing their vaccine. Most pharmacists discarded the bottles even if an extra dose looked to be possible. Days later the FDA came out and said it was probably safe to use the sixth dose while they investigate this further.

♦ Moderna’s vaccine is more in line with what physicians and pharmacists are already used to. It must be stored at -20°C, the temperature of standard pharmacy freezers. It keeps in a regular refrigerator for 30 days. It comes in packs of 100 doses and does not need dilution. Less chance for a mistake or wasted vaccine.

Adverse reactions

Side effects for both the Pfizer and Moderna vaccines were generally mild and temporary, including pain at the injection site, headache, fever, fatigue, chills and muscle and joint pain.

Right after the initial rollout - two workers at a hospital in Alaska suffered allergic reactions soon after receiving Pfizer's vaccine. Both received a treatment consisting of intramuscular epinephrine. One person was kept for observation for at least two nights and the other one recovered quickly and was sent home.

Pfizer has disclosed that several people in the U.K. had a severe allergic reaction to their vaccine but those people had a history of severe allergic reactions. In Alaska, neither person had a history of allergic reactions.

♦ The American College of Allergy, Asthma and Immunology COVID-19 Vaccine Task Force recommends the following guidance related to risk of an allergic reaction on vaccination for those who receive the vaccine.

• The Pfizer-BioNTech COVID-19 vaccine should be administered in a healthcare setting where anaphylaxis can be treated. All individuals must be observed for at least 20-30 minutes after injection to monitor for any adverse reaction. All anaphylactic reactions should be managed immediately, with epinephrine as the first line treatment.

• The Pfizer vaccine should not be administered to individuals with a known history of a severe allergic reaction to polyethylene glycol as it is a component of this vaccine that is known to cause anaphylaxis.

Moderna’s side effects

The FDA said that Moderna reported seven “serious adverse events” in their trial, but none of them was fatal.

Four were attributed to the vaccine, including nausea and vomiting, facial swelling and rheumatoid arthritis.

Fatigue, headaches and muscle pain are the most common side effects.

• On a positive note, the data shows the shots were generally better tolerated by people over 64 who are also among the most vulnerable to the disease.

The FDA said that 9 in 10 participants who received the vaccine felt pain at the injection site, almost 7 in 10 felt fatigued and roughly 6 out of 10 had headaches or muscle pain.

More than 44% of people who received the vaccine reported experiencing joint pain and over 43% reported chills.

♦ Serious adverse reactions occurred in 0.2% to 9.7% of participants and were more common after the second dose than the first.

Nearly 15% of vaccine participants got a fever after either the first or second dose.

Some side effects were hard to shake, though most resolved within a week.

AstraZeneca

The AstraZeneca vaccine is cheap, and can be kept for at least six months in a normal refrigerator, meaning it can be stored in any hospital or pharmacy around the world.

Moderna’s vaccine, by contrast, can be kept in an ordinary refrigerator for a month.

• The Pfizer vaccine is even more sensitive. For most of the time it needs ultra-cold storage at -70°C. It can sit in a standard fridge for only a few days. Rural health clinics have expressed concern about not having equipment to store the Pfizer vaccine.

Moderna says its vaccine is 94.5% effective. Pfizer says the efficacy of its vaccine is 95%. Moderna’s figure is an estimate based on a continuing trial involving 30,000 volunteers. Pfizer’s comes from the final analysis of a trial involving 43,000 people.

♦ The AstraZeneca’s vaccine is the one that has the potential to alter the course of the pandemic. It could be delivered anywhere, including poor countries.

AstraZeneca claims their vaccine is 70% effective. It would be tempting to compare this figure against Moderna and Pfizer, but that is actually hard to do.

The trials count Covid-19 cases in different ways. The AstraZeneca trials checked participants for asymptomatic infection, rather than relying on self-reported symptoms to establish who was infected. The number of cases after vaccination may therefore seem higher than for the Pfizer and Moderna jabs, which relied on self-reporting by patients with a follow-up confirmatory test.

Adverse reactions

There have been two adverse reactions publicly reported during AstraZeneca’s trials.

The first took place in September in the United Kingdom and caused trials to pause temporarily across multiple countries. A few days later the trials resumed. No further details have been shared about the case, so much of what occurred remains unclear.

In addition, in mid-October, a man involved in a trial held in India claimed he experienced neurological and psychological side effects after receiving the vaccine.

India’s medical research regulator, Indian Council of Medical Research, decided the event was no cause for concern and that the trial wouldn’t be paused.

It is difficult to tell if the vaccine caused the neuropsychiatric symptoms or if it was a coincidence.