COVID-19 vaccines currently in use stimulate immunity to the same degree as natural infection without exposing the vaccinated person to the risks associated with the disease

“Merck Scraps COVID Vaccines; Says It’s More Effective To Get The Virus And Recover”
Misleading: Merck stopped COVID-19 vaccine development due to the poor efficacy of its vaccine candidates. The company didn’t say that getting infected with the virus that causes COVID-19 is more effective than getting vaccinated against it. The claim fails to consider the significant risks associated with COVID-19 infections, including death and potential long-term health effects in survivors, such as heart and lung damage or neurological issues.
Vaccination stimulates the development of immunological memory and protects individuals from infectious diseases in the same way that natural infection does. However, vaccination is safer than natural infection because it doesn’t expose the person to the risks associated with the disease. COVID-19 poses serious health risks to infected individuals that can lead to potential long-term health effects or death. Therefore, COVID-19 vaccines are an important tool to minimize complications from the disease.

FULL CLAIM: “Merck Scraps COVID Vaccines; Says It’s More Effective To Get The Virus And Recover”


On 25 January 2021, the U.S biopharmaceutical company Merck announced its decision to stop  the development of its COVID-19 vaccine candidates. This article, published on 26 January 2021 by Summit News, reported on Merck’s announcement and claimed that Merck said “it’s more effective to get the virus and recover”. In short, the article framed Merck’s statement as an encouragement to get infected with the virus that causes COVID-19 instead of getting the vaccine. The article was widely shared on social media, receiving more than 68,000 interactions on Facebook in two days, according to the social media analytics tool CrowdTangle.

Many social media posts shared the Summit News article, claiming that “studies showed people better off catching virus and recovering” (here), or “Merck says skip vaccines” (here). These interpretations are misleading, as we explain below.

In a press release, Merck explained the reasons for discontinuing the development of its two COVID-19 vaccine candidates:

This decision follows Merck’s review of findings from Phase 1 clinical studies for the vaccines. In these studies, both V590 and V591 were generally well tolerated, but the immune responses were inferior to those seen following natural infection and those reported for other SARS-CoV-2/COVID-19 vaccines.”

The Summit News article misrepresents Merck’s reference to natural infection, claiming that “it’s more effective to get the virus and recover” than to get vaccinated. Comparing the efficacy of different vaccine candidates can be difficult because clinical trials use different methods to measure immune responses. Therefore, researchers often measure antibody levels in recovering COVID-19 patients as a reference[1]. However, Merck never said that it is better to get COVID-19 infection and recover than to get vaccinated. Instead, the company explained that it stopped COVID-19 vaccine trials because its vaccine candidates induced a lower immune response than other COVID-19 vaccines and than COVID-19 infection.

Furthermore, the claim that natural infection is more efficient than vaccination is misleading as it fails to consider the high transmissibility of the virus and potential sequelae, or consequences of a disease, that COVID-19 infection may cause in people. The main benefit of vaccines over natural infection is to confer immunity against a disease without exposing the person to it. While it is true that most COVID-19 infections involve mild, short-term symptoms, the rapid spread of COVID-19 caused more than 124,000 hospitalizations and 423,000 deaths in the U.S at the time of this review’s publication.

Clinical evidence shows that COVID-19 can cause a range of outcomes that go far beyond death or recovery. A significant proportion of people infected with COVID-19 continue suffering “long COVID”. This condition involves symptoms such as loss of smell and taste, extreme fatigue, shortness of breath, and cognitive issues that can last for months[2]. Even more concerning, COVID-19 infections might cause lifelong problems in some survivors, including lung and heart damage and neurological issues[3,4], as Health Feedback explained in this earlier review. Therefore, vaccines represent an essential tool to minimize the considerable risks associated with COVID-19 infection.

The headline of the Summit News article further suggests that natural immunity is superior to vaccination in general. Such is the interpretation in some posts, “The virus has a 99.9% survival rate. Get it, recover, move on with life!” The fact that one particular vaccine candidate, like the ones from Merck, produces lower antibody levels doesn’t mean that all COVID-19 vaccines generate a weaker response than natural infection. In fact, BioNTech-Pfizer and Moderna vaccines induce an immune response several times higher than that observed in recovering COVID-19 patients[5,6]. Although most vaccines don’t induce such a strong immune response, they are still the safest way of acquiring immunity. The Children’s Hospital of Philadelphia explains:

It is true that natural infection almost always causes better immunity than vaccines. Whereas immunity from disease often follows a single natural infection, immunity from vaccines usually occurs only after several doses. However, the difference between vaccination and natural infection is the price paid for immunity […].”

Health experts warn that developing multiple COVID-19 vaccines with different characteristics will be essential to control the pandemic. For example, one COVID-19 vaccine may prevent the disease with higher efficacy than others in a specific group of people, like older people, children, or people with certain underlying health conditions. Furthermore, the pandemic situation requires producing and rolling out vaccines at an unprecedented scale and rate. The availability of multiple COVID-19 vaccines would improve the production and adequate delivery of sufficient doses to anyone that needs them.

As of 27 January 2021, researchers are testing 66 COVID-19 vaccine candidates in clinical trials, according to the New York Times Coronavirus Vaccine Tracker. However, emergency-use authorization of the mRNA vaccines from BioNTech-Pfizer and Moderna in the U.S. and other countries set a high threshold for other vaccine developers. With an efficacy of over 90% and a faster manufacturing process, these vaccines may prompt developers to drop other vaccine candidates that don’t elicit comparable immune responses[7].

In summary, Merck didn’t say that natural infection is more effective in generating immunity than a COVID-19 vaccine. Instead, the company explained that they stopped COVID-19 vaccine development because its vaccine candidates in particular were less efficient than other vaccines and than natural COVID-19 infection. Given the potential risks that COVID-19 infection carries, vaccines are an essential tool to minimize disease exposure and its subsequent consequences on health.



Published on: 29 Jan 2021 | Editor:

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