Are Covid mRNA vaccines risky? What the Experts Say: QuickTake

Photographer: Micah Green / Bloomberg

When it became clear in early 2020 that the Sars-CoV-2 virus posed a pandemic threat, researchers who explored an innovative way to manufacture vaccines saw an opportunity. Experimental messenger RNA vaccines had been recognized for years for their potential speed and flexibility in a rapidly evolving epidemic, and were among the first inoculations of Covid to pass into human trials. The effort paid off when, late last year, vaccines Moderna Inc. and the Pfizer Inc./The BioNTech SE partnership was the first to prove effective. Because the technology is so new, however, these vaccines are particularly vulnerable to disinformation campaigns aimed at dissuading people from taking the shots.

1. How do mRNA vaccines work?

They work differently from previous generations of vaccines. Instead of presenting the body with an inactivated or weakened version of a virus or a piece of it, they temporarily turn the body’s cells into tiny vaccine factories. They do this by using synthesized versions of something called messenger RNA, a molecule that normally carries the genetic coding of DNA from a cell to its protein-making machinery. In this case, the mRNA tells the body to make the spike protein that Sars-CoV-2 uses to get into cells. This, in turn, stimulates the body to make long-lasting antibodies against the virus. Messenger RNA vaccines are faster to develop than traditional vaccines because their production does not require the growth of viruses or viral proteins inside living cells. In addition, the modular nature of mRNA makes the design of new vaccines relatively straightforward. It only took a few days for researchers in January 2020 to find the mRNA sequence used in Moderna’s Covid vaccine.

2. What do we know about their effectiveness?

In its Phase 3 trial involving more than 30,000 participants, Moderna’s vaccine was 94% effective in preventing symptomatic cases of Covid, according to the company’s file to the U.S. Food and Drug Administration. There were no cases of serious illness in those who received the vaccine, compared to 30 in the placebo group. Pfizer’s vaccine was 95% effective in stopping the disease in its Phase 3 trial involving more than 43,000 participants, according to results published in the New England Journal of Medicine after the peer review process, in which research is reviewed by experts in the same field. Although there were fewer severe cases in this trial, the limited data was consistent with protection against severe disease. Results in the real world are just starting to come in, but they are looking good so far. Data from Israel’s largest healthcare organization revealed that after two doses Pfizer injection was 94% effective against symptomatic Covid and avoided 87% of Covid hospitalizations, peer reviewer says . published results.

3. What do we know about their safety?

Both vaccines can induce strong reactions, especially after the second stroke, including headache, muscle and joint pain, and fever. For example, in the Moderna trial, after the second dose of the shot, most people under 65 have experienced fatigue and muscle pain; about half had chills and 1 in 6 people had a fever. With both vaccines, these side effects are less common in the elderly. After the vaccine was authorized for use, authorities began to notice rare cases of severe allergic reactions. One theory is that these are caused by the Lipid nanoparticles that coat vaccines, helping to transport them around the body. These events are rare, ranging from 2-5 cases per million shots administered, according to data through Jan. 18 from the U.S. Centers for Disease Control and Prevention. They can usually be treated with adrenaline, also known as epinephrine; a small minority of cases required intubation. A study of data up to Feb. 18 from Massachusetts General Hospital has suggested a higher rate of severe allergic reactions, approximately 2.5 cases per 10,000 injections, but still concluded that the overall risk “remains extremely low”. Meanwhile, a separate study from Mass General showed that some people delayed rashes after receiving Moderna’s vaccine. While sometimes dramatic, these rashes aren’t dangerous, the researchers said.

4. Who is spreading misinformation about vaccines?

Traditional anti-vaccine campaigners have increasingly associate with numbers on the alt-right, a predominantly online US-based political movement whose members espouse extremist beliefs typically centered around ideas of white nationalism. High level curators, including Fox News personality Tucker Carlson has raised doubts about Covid vaccines in general. According to the US State Department, several online platforms related to Russian intelligence spread misinformation about mRNA vaccines; Moderna and Pfizer are companies based in the United States. A foundation of the Kaiser family A survey found that people who refuse the vaccine disproportionately depend on Facebook for their information, while people who want the vaccine are more likely to read newspapers or watch TV news on the network.

5. What are they saying?

• These steps have been overlooked in vaccine development and licensing: it’s true that vaccines hit the market in record time, but that’s not because no testing step has been skipped. Companies sped up the process by performing some testing steps in parallel, and in the case of Moderna’s vaccine, the U.S. government took financial risk by paying to prepare for manufacture before the results were known.
• Vaccines have never been approved by the FDA: This is true in the sense that the agency has so far only given emergency use authorization. It’s a pre-existing mechanism created to accelerate access to medical countermeasures in the event of a public health emergency such as the Covid pandemic. The The FDA established in advance that to obtain approval, Covid vaccines must be at least 50% effective in preventing disease in large-scale trials and must demonstrate their safety with two months of data from follow-up on trial participants. In addition, the vaccines were checked by a panel of independent advisers. Moderna and Pfizer said they plan to seek regular approval for the vaccines this year.
• Critics have started labeling mRNA vaccines as a form of gene therapy, suggesting that the injections might somehow damage your DNA: they don’t. While the messenger RNA they employ is a type of genetic material, vaccines differ from what is generally considered to be gene therapy in that they do not alter the DNA inside cells. “They don’t affect or interact with our DNA in any way,” the Centers for Disease Control and Prevention Explain. In fact, mRNA molecules in vaccines, which are short lived, do not enter the nucleus of cells, where DNA is stored, notes the CDC.
• That the lipid nanoparticles of vaccines contain antifreeze: this is not true. The antifreeze contains ethylene glycol, which is toxic. Lipid nanoparticles instead include polyethylene glycol, an inert compound found in everyday products like toothpaste and shampoo and in many medications, including laxatives.
• Whether vaccines can cause antibody-dependent improvement, or a worse case of illness in those who fall ill despite inoculation: that was a theoretical concern when testing of the Covid vaccines began. There were indications of this problem in animal studies of some vaccines for Severe Acute Respiratory Syndrome (SARS), which is caused by a coronavirus linked to SARS-CoV-2. However, no indication of this has appeared in human trials of mRNA vaccines for Covid, according to Stanley Perlman, a coronavirus researcher at the United States. University of Iowa, which served on the FDA advisory panel that reviewed vaccines.
• That we don’t know the long-term effects of vaccines: this is always the case with new vaccines. But the side effects of vaccines usually appear in the a few months after vaccination, which is why the FDA insisted on two months of safety data before authorizing them. Reports of adverse events since then have not detected any death patterns that would indicate a problem with the vaccines, according to the CDC.
• That there are more reports of adverse events for Covid vaccines than for influenza vaccines: not a proper or meaningful comparison, says Aaron Kesselheim, professor of medicine Harvard School of Medicine. The number of such reports tends to increase when a treatment or vaccine makes headlines, and nothing has made the headlines more than Covid vaccines. In the United States, these reports can be filed by anyone and does not constitute confirmation that a vaccine has caused an adverse event. Due to the large number of vaccinees, some unlucky people will get sick and die even shortly after receiving vaccines, regardless of the vaccine.

The reference shelf