Israel Prepares for COVID Vaccine: Is It Safe, What Are the Side Effects? Experts Provide Answers

Is the coronavirus vaccine safe? What about side effects? Researchers and doctors answer dozens of readers’ questions, giving you all the information you need before being vaccinated

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An illustration of a vaccination.

An unprecedented vaccination campaign against the coronavirus is about to get underway. This is the first, important step on the road back to normal life. Naturally, the tremendous speed with which the vaccine was developed is raising many questions among people who want to safeguard their health.

Despite the accelerated process, numerous experts say that getting vaccinated is a wise choice. Prof. Lior Zangi works at the Icahn Medical School at Mount Sinai, New York, and he specializes in the RNA technology that was used to develop the Moderna and Pfizer-BioNTech vaccines. “From what we know about the coronavirus from the past year, and what we know about vaccines in general from decades of research and about coronavirus vaccines in particular in the past six months, we can conclude that the benefit of the vaccine outweighs the risks,” he told Haaretz.

There were 44,000 participants in the Pfizer trial and 30,000 in Moderna’s. According to the U.S. Food and Drug Administration, no serious side effects were observed in any of the volunteers. Both companies reported that their vaccines have a high efficacy rate among younger age groups, as well as for those 65 and older.

Relying on researchers, doctors and official documents, below are the answers to dozens of questions sent in by readers. They are divided by subject: safety; efficacy; how the vaccine campaign will be conducted; and how the vaccine works.


Nurse Helen Cordova showing her vaccination record card after receiving the Pfizer-BioNTech COVID-19 vaccine at Kaiser Permanente Los Angeles Medical Center in Los Angeles, December 14, 2020. Credit: Jae C. Hong/AP

Are there any short-term side effects after I’m injected?

According to documents Pfizer submitted to the FDA, no serious side effects were observed during the trial. The side effects reported included temporary pain or itching at the injection site, fatigue, headache, muscle ache, dizziness, joint pain and fever. The most significant reports of side effects occurred primarily after the second dose of the vaccine and were more common among people aged under 55.

Some people may have to take a day off from work or school after receiving the second shot. Although these are unpleasant sensations, they indicate that the body’s immune system is responding to the vaccine and working to create long-term immunity.

How do I know the vaccine is safe in the long term?

At this stage, there is no way of knowing for certain if the vaccines will cause long-term side effects, since the clinical trials only began last March. However, in the history of vaccine development, side effects have been found to mainly appear shortly after the inoculation, or within a few weeks at most. Since the vaccine trials began, no such side effects were reported among any of the tens of thousands of volunteers.

Were the vaccines tested on pregnant women and women of childbearing age? Will the vaccine affect the fetus?

The vaccine has not yet been tested on pregnant or breastfeeding women, so at this stage they will not be inoculated. Due to the lack of information on this, women of childbearing age will be asked if they are pregnant before receiving the vaccine.

Frances Gogh receiving the first of two Pfizer/BioNTech COVID-19 vaccine jabs, at Guy's Hospital, London, December 8, 2020.Credit: VICTORIA JONES - AFP

Women between the ages of 18-85 took part in the trials and no significant difference in response was noted between men and women. At this stage, there is no way to know about rare side effects.

What do we know about the safety of RNA vaccines? Could it create long-term genetic changes? Has this new technology been tried before?

Treatments with messenger RNA (mRNA) have been studied for about a decade, including on humans, and to date no safety issues have been found with this method. This is the first treatment approved with this technology. Since 2017, about 1,000 subjects have been vaccinated as part of research into RNA vaccines against viruses such as cytomegalovirus, Zika, influenza and rabies, and no unusual side effects were observed.

Despite the vaccine’s name, RNA molecules quickly degrade (in the body and generally), and the RNA does not affect the DNA in the cell nucleus where the genes are located. So the vaccine doesn’t affect human DNA.

“Because RNA technology gives a transient, controlled expression of the encoded protein without side effects in clinical trials, there’s a high likelihood that it’s safe for use in humans and will continue to serve us in other vaccines and the creation of new drugs with RNA,” Zangi says.

How can I be sure the Health Ministry in Israel did the necessary research? Which agencies are approving the vaccine?

The registration and approval process in Israel is handled by the pharmaceutical division of the Health Ministry’s Directorate of Medical Technologies, Informatics and Research. The Health Ministry does not automatically accept the recommendations of the FDA. It does an independent assessment of the findings and also receives recommendations from an advisory committee of specialist physicians.

A member of the medical staff holding a phial of the Pfizer/BioNTech COVID-19 vaccine jab, at Guy's Hospital, London, December 8, 2020.Credit: VICTORIA JONES - AFP

As is happening in many other countries worldwide, the regulation process regarding coronavirus vaccines in Israel is advancing on two tracks simultaneously. The first is a fast track for granting emergency approval, based on all the findings and research material the companies can present at this point. The longer track for granting permanent approval relies on data accumulated as the vaccine is distributed to the general population and is tested in trials on population groups that have yet to be examined.

The approval process is based on numerous, detailed regulations developed over many years. The health agencies of many countries closely monitor decisions by the FDA, the world’s premier agency for approving drugs and medical devices.

Could the vaccine heighten the risk of cancerous mutations?

RNA-based vaccines do not reach the cell nucleus and human DNA, so they can’t affect the genes in DNA. Thus, there is little cause to fear the creation of cancerous mutations.


Wouldn’t it be better to develop antibodies naturally as a result of infection?

The body develops antibodies in two ways. The first is through a natural process in which when one is exposed to the virus, the body’s immune system identifies the virus as an invader, produces enough antibodies to combat it and ultimately produces immune memory.

Medical staff applaud after patient George Dyer was given the hospital's inaugural dose of the Pfizer/BioNTech Covid-19 vaccine at Croydon University Hospital, south London, December 8, 2020.Credit: DAN CHARITY - AFP

The second possibility is artificial: Creating recognition between the immune system and the virus on the basis of relevant features (such as the structure of the viral coating, without exposure to the potentially harmful genetic load that penetrates the cell) in order to stimulate the immune system to produce antibodies.

Data collected by researchers since the start of the pandemic indicates that those who recover from the virus have strong natural immunity against recurrent infection. However, acquiring natural immunity entails full exposure to the virus, with all that implies: the risk of developing the illness, which may range from mild to fatal, and the risk of infecting others, some of whom may have weak immune systems.

The virus has taken the lives of people from all age groups, not just the elderly, and many people who have recovered from the virus still struggle with various long-term symptoms months later. The big advantage of the vaccine is that it enables people to bypass the highly unpredictable illness.

Is the vaccine effective against all strains of coronavirus? What about winter viruses?

The vaccine is designed to protect against the SARS-CoV-2 coronavirus, the strain that causes COVID-19. The virus is constantly mutating, but for the most part these are genetic changes that don’t alter its characteristics and structure. Thus, the vaccine is effective against the virus in China, the United States and Israel, despite the mutations it has undergone since it originated.

Are those who already had the coronavirus now immune? What happens if someone who’s recovered from the coronavirus gets vaccinated?

It’s still unclear how much immunity against reinfection someone who’s recovered from the coronavirus has, and for how long. For this reason, the World Health Organization recommends immunizing people who have recovered from the virus – in order to streamline the vaccination campaigns and because of the uncertainty regarding the extent and duration of natural immunity.

A worker pouring dry ice into boxes containing the Pfizer-BioNTech Covid-19 vaccine as they are prepared to be shipped at the manufacturing plant in Kalamazoo, Michigan, December 13, 2020.Credit: MORRY GASH - AFP

Pfizer’s clinical trial also included recovered coronavirus patients who had antibodies before they received the vaccine, and they didn’t experience any unusual side effects. Nonetheless, at this stage, due to the need to prioritize those who are at higher risk, such people are at the bottom of the list for receiving the vaccine – even if they meet other parameters that would place them in a high priority category (such as advanced age or being a front-line medical worker). As the vaccine campaign progresses and the stock of vaccines grows, the authorities will also invite recovered coronavirus patients to be vaccinated.

Why should I get a vaccine that was developed so much more quickly than usual? I’m young and healthy and at low risk of getting sick. Why risk it?

Since the pandemic arrived in Israel, some 350,000 Israelis have been confirmed as infected and approximately 3,000 have died. Many people have become seriously ill, including young people. Some who have recovered still suffer from symptoms that are disrupting their lives. Then there’s the vast social and economic damage caused by the virus outbreak. The number of victims worldwide is huge.

Yes, at this stage, the safety picture concerning the coronavirus vaccines is incomplete, and no one can guarantee safety or efficacy. This will become clearer in time. But deciding not to get vaccinated entails another type of risk: the possibility of becoming infected with a virus for which there is still no effective treatment and that, even when not fatal, can cause significant harm to one’s health.

Also, the vaccination of a young and health person is not intended solely to protect that person but to help reach a herd immunity effect and suppress the pandemic.

Getting back to normal life and reviving the economy will only be possible with the vaccination of the general population.


Medical staff working in the Vaccination Hub at Croydon University Hospital, south London on December 8, 2020, where the Pfizer/BioNTech Covid-19 vaccine is being administered.Credit: DAN CHARITY - AFP

Can I choose a specific version of the vaccine? Will I know which vaccine I receive? Might I only be offered the Russian “Sputnik 5” vaccine?

People getting vaccinated are not expected to be given a choice of different vaccines. For now, the guidelines and arrangements are only relevant to the Pfizer vaccine. Israel has not signed any agreement to purchase the vaccine developed in Russia. Hadassah Medical Center ordered 1.5 million doses of the Russian vaccine and says it plans to request approval from the Health Ministry to use the vaccine in Israel if its trial is successful.

Will someone who refuses to be vaccinated be subject to sanctions? Will there be positive incentives, such as being permitted entry to cinemas and malls?

Compliance with the vaccination campaign is one of the major challenges for the effort ahead and the Health Ministry is currently formulating a public PR campaign to be used ahead of and during the vaccination campaign.

Section 19 of the Public Health Ordinance (1940) permits the imposition of sanctions and fines on someone who refuses to be vaccinated. The Health Ministry has been examining the feasibility of advancing legislation that would permit the imposing of sanctions, such as a rule that would bar unvaccinated school employees or medical staff from entering their workplace. However, the ministry also understands that in order to boost compliance, information, transparency, personal examples and positive incentives are needed. Ministry officials have explicitly stated that there will be no mandatory vaccination in Israel.


How long does the RNA from the vaccine remain in the body? An RNA vaccine enters the cell and causes it to produce foreign proteins. What makes it stop producing them?

RNA molecules degrade in the body within hours, and the nucleotides from which they are made are excreted in the urine. When the cell no longer has the RNA production instructions, the spike protein production ceases too. In any case, the RNA only reaches a minuscule number of cells compared to the number of cells that are replaced in the body daily, and there is no mechanism that would enable it to replicate and be preserved in the cells for a long time or to move to other cells.

Millions of people will be receiving millions of RNA molecules. What will stop the RNA molecules from the vaccine being swallowed up by a bacterium or virus that will start producing them?

Coronavirus vaccines being stored at Shoham, December 10, 2020.Credit: אלעד מלכה

This isn’t possible. “There’s no known mechanism by which the RNA of the vaccine could pass into and integrate with a virus,” says Prof. Igor Ulitsky, an RNA researcher at the Weizmann Institute of Science, Rehovot. That sort of risk could only be relevant if DNA molecules and not RNA molecules were being injected. “It just doesn’t work that way,” Zangi agrees.

They’ve been trying to produce an mRNA vaccine for years without success. Why has it worked this time? What went wrong in the past?

RNA molecules were first synthesized in a laboratory in the 1980s. But it took 30 years to develop the technologies that would enable enough of them to reach the body’s cells to generate a therapeutically significant response.

In recent years, there has been great progress in the development of RNA-based therapies, but the clinical studies focused on developing vaccines for diseases like the Zika virus, in which vaccine testing is very complicated, or for which the traditional methods failed to produce effective vaccines. As a result, progress was slow. The experience with the coronavirus will likely accelerate this type of vaccine development. ‏

Ugur Sahin, CEO and co-founder of German biotech firm BioNTech, September 17, 2020.Credit: FABIAN BIMMER/REUTERS

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