Astra Zeneca Vaccine Image review

This vaccine is a viral vector vaccine, similar to Johnson and Johnson and SputniK.

Mechanism of Action

Vaccine is composed of a recombinant, replication-incompetent human adenovirus type 26 vector that after entering human cells, expresses the SARS-CoV-2 spike (S) antigen without virus propagation

An immune response elicited to the S antigen protects against COVID-19

So-called viral vector shots - also used by several Chinese COVID-19 vaccine developers - use harmless modified viruses as vehicles, or vectors, to carry genetic information that helps the body build immunity against future infections.

However, there is a risk that the body also develops immunity to the vector itself.

Most vector-vaccine developers have opted to use an adenovirus, a harmless class of common-cold viruses.

"The experience with adenoviruses has been for many years that vectors can be intercepted by the immune system after repeat injections," said Bodo Plachter, deputy director of the Institute of Virology at Mainz University's teaching hospital.

AstraZeneca Vaccine Faces Resistance in Europe After Health Workers Suffer Side Effects

PARIS (Reuters) - Health authorities in some European countries are facing resistance to AstraZeneca's COVID-19 vaccine after side-effects led hospital staff and other front-line workers to call in sick, putting extra strain on already-stretched services.

Such symptoms, as reported in clinical trials for the AstraZeneca shot, can include a high temperature or headache and are a normal sign that the body is generating an immune response. They usually fade within a day or so.

The other shots approved in Europe, developed by Pfizer and Moderna, have been linked to similar temporary side-effects, including fever and fatigue.

But with the AstraZeneca shot the latest to be rolled out, health authorities in France have issued guidance to stagger giving the shot, two regions in Sweden paused vaccinations, and in Germany some essential workers are refusing it.

A spokesman for AstraZeneca said: "Currently, the reactions reported are as we would expect based on the evidence gathered from our clinical trial programme."

People receiving the vaccine are closely monitored through routine pharmacovigilance activities, the Anglo-Swedish drug maker said, adding that it was continuing to keep a close eye on the situation.

"There have been no confirmed serious adverse events," the spokesman said.

'MORE SIDE-EFFECTS'

In France, which started administering the AstraZeneca shot on Feb. 6, staff at a hospital in Normandy experienced stronger side-effects than seen with the alternative vaccine from Pfizer and German partner BioNTech.

"AstraZeneca caused more side-effects than the Pfizer vaccine," said Melanie Cotigny, communications manager at Saint-Lo hospital in Normandy.

"Between 10% and 15% of those vaccinated may have side-effects from this vaccination, but it is only a feverish state, fevers, nausea and within 12 hours it goes away."

Following similar reports from other hospitals, the French medicines safety agency said on Feb. 11 that such side-effects were "known and described" but should be subject to surveillance with regard to their intensity.

It also issued guidance to stagger vaccinations of front-line staff working together in teams to minimise the risk of disruption to operations.

The agency put out the advice after receiving 149 alerts of often strong flu-like side-effects from the AstraZeneca vaccine. During this period a total of 10,000 people received the shot nationwide.

Some U.S. hospitals and other organisations with front-line staff adopted a similar strategy when the country's vaccination programme started in December. The United States is administering shots from Pfizer/BioNTech and Moderna.

In Britain, home to the AstraZeneca vaccine developed at Oxford University, the policy has been to make vaccinations readily available to hospital staff. As many work shifts, that naturally spaces out the process.

The issues in France highlight how some doctors and hospitals are still learning how best to administer vaccines as governments race to tame the pandemic and get shots in arms as quickly as possible.

It's also the latest setback for the French vaccination campaign which has been criticised for a slow start. Last week, the government said just over 3% of the population had received their first dose.

In Sweden, two of 21 healthcare regions paused vaccinations of workers last week after a quarter called in sick after getting the AstraZeneca shot.

The Sormland and Gavleborg regions said that around 100 out of 400 people vaccinated had reported fever or fever-like symptoms. Most cases were mild and in line with previously reported side-effects.

Both regions said they would resume vaccinations, and the Swedish Medical Products Agency saw no reason to change its vaccination guidelines.

NO SHOWS

AstraZeneca's adenovirus vector-based vaccine is the third to win regulatory approval in the European Union.

As part of the European Medicines Agency's positive recommendation on Jan. 29, the watchdog concluded it was about 60% effective, compared to more than 90% for the vaccines from Pfizer/BioNTech and Moderna.

It also deemed the product safe to use and it will monitor reports of side-effects as a matter of routine.

In Germany, Health Minister Jens Spahn responded on Wednesday to reports that essential workers were reluctant to receive the AstraZeneca shot after some experienced strong side-effects, saying it was both safe and effective.

"I would be vaccinated with it immediately," Spahn told reporters.

Like most European countries, German states typically do not offer people a choice of which vaccine they will get, leading in some cases to people not turning up to appointments to get the AstraZeneca vaccine.

Germany has taken delivery of 737,000 doses from AstraZeneca but only administered 107,000, according to figures from the health ministry and the Robert Koch Institute that leads its pandemic response.

"This vaccine is an excellent way to prevent serious COVID disease," said the health ministry in the eastern state of Saxony. "Still, we note that there are still vacant vaccination dates for AstraZeneca.

"From our point of view, it is wrong that this vaccine is available but not being used," it said, adding that it was reallocating spare shots to teachers and public health workers.

Myth Busting: SARS-CoV-2 Vaccine

We know that 68 million people in the United States and 244 million people worldwide have already received messenger RNA (mRNA) SARS-CoV-2 vaccines (Pfizer/BioNTech and Moderna). So for the short-term side effects we already know more than we would know about most vaccines.

Dr Michael Pichichero

What about the long-term side effects? There are myths that these vaccines somehow could cause autoimmunity. This came from three publications where the possibility of mRNA vaccines to produce autoimmunity was brought up as a discussion point.1-3 There was no evidence given in these publications; it was raised only as a hypothetical possibility.

There's no evidence that mRNA or replication-defective DNA vaccines (AstraZeneca/Oxford and Johnson & Johnson) produce autoimmunity. Moreover, the mRNA and replication-defective DNA, once it's inside of the muscle cell, is gone within a few days. What's left after ribosome processing is the spike (S) protein as an immunogen. We've been vaccinating with proteins for 50 years and we haven't seen autoimmunity.

MYTH: The Vaccines Aren't Safe Because They Were Developed so Quickly

These vaccines were developed at "warp speed" — that doesn't mean they were developed without all the same safety safeguards that the Food and Drug Administration requires. The reason it happened so fast is because the seriousness of the pandemic allowed us, as a community, to enroll the patients into the studies fast. In a matter of months, we had all the studies filled. In a normal circumstance, that might take 2 or 3 years. And all of the regulatory agencies — the National Institutes of Health, the FDA, the Centers for Disease Control and Prevention — were ready to take the information and put a panel of specialists together and immediately review the data. No safety steps were missed. The same process that's always required of phase 1, of phase 2, and then at phase 3 were accomplished.

The novelty of these vaccines was that they could be made so quickly. Messenger RNA vaccines can be made in a matter of days and then manufactured in a matter of 2 months. The DNA vaccines has a similar timeline trajectory.

MYTH: There's No Point in Getting the Vaccines Because We Still Have to Wear Masks

Right now, out of an abundance of caution, until it's proven that we don't have to wear masks, it's being recommended that we do so for the safety of others. Early data suggest that this will be temporary. In time, I suspect it will be shown that, after we receive the vaccine, it will be shown that we are not contagious to others and we'll be able to get rid of our masks.

MYTH: I Already Had COVID-19 so I Don't Need the Vaccine

Some people have already caught the SARS-CoV-2 virus that causes this infection and so they feel that they're immune and they don't need to get the vaccine. Time will tell if that's the case. Right now, we don't know for sure. Early data suggest that a single dose of vaccine in persons who have had the infection may be sufficient. Over time, what happens in the vaccine field is we measure the immunity from the vaccine, and from people who've gotten the infection, and we find that there's a measurement in the blood that correlates with protection. Right now, we don't know that correlate of protection level. So, out of an abundance of caution, it's being recommended that, even if you had the disease, maybe you didn't develop enough immunity, and it's better to get the vaccine than to get the illness a second time.

MYTH: The Vaccines Can Give Me SARS-CoV-2 Infection

The new vaccines for COVID-19, released under emergency use Authorization, are mRNA and DNA vaccines. They are a blueprint for the Spike (S) protein of the virus. In order to become a protein, the mRNA, once it's inside the cell, is processed by ribosomes. The product of the ribosome processing is a protein that cannot possibly cause harm as a virus. It's a little piece of mRNA inside of a lipid nanoparticle, which is just a casing to protect the mRNA from breaking down until it's injected in the body. The replication defective DNA vaccines (AstraZeneca/Oxford and Johnson & Johnson) are packaged inside of virus cells (adenoviruses). The DNA vaccines involve a three-step process:

• 1. The adenovirus, containing replication-defective DNA that encodes mRNA for the Spike (S) protein, is taken up by the host cells where it must make its way to the nucleus of the muscle cell.

• 2. The DNA is injected into the host cell nucleus and in the nucleus the DNA is decoded to an mRNA.

• 3. The mRNA is released from the nucleus and transported to the cell cytoplasm where the ribosomes process the mRNA in an identical manner as mRNA vaccines.

MYTH: The COVID-19 Vaccines Can Alter My DNA

The mRNA and replication-defective DNA vaccines never interact with your DNA. mRNA vaccines never enter the nucleus. Replication-defective DNA vaccines cannot replicate and do not interact with host DNA. The vaccines can't change your DNA.

Here is a link to YouTube videos I made on this topic:

Here is a photo of me receiving my first SARS-CoV-2 shot (Moderna) in January 2021. I received my second shot in February. I am a lot less anxious. I hope my vaccine card will be a ticket to travel in the future.

Pichichero is a specialist in pediatric infectious diseases and director of the Research Institute at Rochester (N.Y.) General Hospital. He has no conflicts of interest to report.

References:

1. Peck KM and Lauring AS. J Virol. 2018. doi: 10.1128/JVI.01031-17.

2. Pepini T et al. J Immunol. 2017 May 15. doi: 10.4049/jimmunol.1601877.

3. Theofilopoulos AN et al. Annu Rev Immunol. 2005. doi: 10.1146/annurev.immunol.23.021704.115843.