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No evidence that the low COVID-19 case rate in Sweden is due to herd immunity; vaccines don’t lead to new variants of SARS-CoV-2

Posted on:  2021-11-29

Key takeaway

Although Sweden started its COVID-19 vaccination campaign later than other countries, as of November 2021, its vaccine coverage is similar to that of the U.S. and the U.K. There is no evidence that the low number of COVID-19 cases in Sweden is due to herd immunity rather than vaccination, which scientific evidence has shown to reduce COVID-19 transmission. There is no evidence supporting the claim that COVID-19 vaccines lead to more dangerous variants. The evidence from clinical trials and the monitoring of vaccination campaigns show that COVID-19 vaccines are effective at reducing COVID-19 hospitalizations and deaths.

Reviewed content


“Sweden obliterates the lie of ‘vaccines’ as ticket to ending pandemic”; mass vaccination create vaccine-mediated viral enhancement

Source: The Blaze, Daniel Horowitz, 2021-11-16

Verdict detail

Factually inaccurate: Contrary to the article, Sweden did experience a spike in COVID-19 cases in July 2021 due to the Delta variant, which has since become the predominant variant in the country.
Inadequate support: There’s no evidence that COVID-19 vaccines lead to the generation of variants. In fact, the Delta variant was first detected months before vaccines received authorization. The article also repeatedly claimed that Sweden achieved herd immunity, but offered no evidence for this claim.

Full Claim

“The fact that Sweden has never gotten a Delta wave demonstrates that natural immunity alone would have ended this pandemic”; “vaccinologists like Geert Vanden Bossche and Luc Montagnier were correct when they predicted that mass vaccination with a suboptimal, non-sterilizing vaccine in middle of a pandemic would create vaccine-mediated viral enhancement”


Various countries experienced a rise in COVID-19 cases in 2021 despite ongoing vaccination campaigns. Certain outlets took advantage of the Delta wave to question the effectiveness of the COVID-19 vaccines. An example of this is this article by Daniel Horowitz, published in The Blaze on 16 November 2021. Horowitz previously authored articles that contained inaccurate and misleading information about face masks and COVID-19 vaccines, which Health Feedback addressed here and here.

The article became viral shortly after publication—as of 23 November 2021, it received more than 7,000 engagements on Facebook according to social media analytics tool CrowdTangle. However, as we will explain below, the claims made in the article are inaccurate and unsubstantiated.

The article drew attention to the low number of COVID-19 cases in Sweden in November 2021 relative to case numbers in other countries and claimed that this occurrence “obliterates the lie of ‘vaccines’ as ticket to ending pandemic”. The article also linked vaccines to the increase in new COVID-19 cases, claiming that this was evidence that the vaccines cause “vaccine-mediated viral enhancement”, as scientists such as Geert Vanden Bossche and Luc Montagnier alleged.

However, the decrease in COVID-19 cases, deaths and hospitalizations in Sweden after July 2021 coincides in time with the increase in the proportion of vaccinated people in the country, contradicting this claim (Figure 1).

Figure 1. COVID-19 vaccine doses administered, new cases of COVID-19, patients in ICU and new deaths due to COVID-19 in Sweden, relative to population in the country. Data retrieved on 26 November 2021. Source: Our World in Data

Claim 1 (Inaccurate): “Sweden has never gotten a Delta wave”

The article stated that “the Swedes never experienced a single Delta wave”, but Sweden did see a rise in COVID-19 cases in which Delta was the dominant variant in July 2021. Delta has since become the prevalent variant of SARS-CoV-2 in the country.

Although the numbers of new cases since July 2021 were lower than those experienced during the previous two waves, they were similar to those experienced by Sweden during the first wave of COVID-19, between March to August 2020. Furthermore, the number of cases due to Delta in the country is on the rise at the time of this review’s writing (Figure 2).

Overall, since Delta became the predominant variant in Sweden in July 2021, there have been more than 105,000 new cases and around 500 deaths due to COVID-19. This accounts for approximately 9% of COVID-19 cases in Sweden (out of a total of 1.2 million cases since the start of the pandemic, as of 26 November 2021), and about 3% of all COVID-19 deaths in the country (out of a total of 15,145 deaths).

Figure 2. Daily new confirmed cases of COVID-19 per million people in Sweden, 7-day rolling average. Data retrieved on 26 November 2021. Source: Our World in Data.

Claim 2 (Inaccurate): COVID-19 vaccines led to “vaccine-mediated viral enhancement”

The article claimed that COVID-19 vaccination made SARS-CoV-2 more dangerous due to a phenomenon called “vaccine-mediated viral enhancement”. This may be a reference to an earlier claim that the COVID-19 vaccines cause antibody-dependent enhancement (ADE). This claim was debunked by Health Feedback here. Furthermore, there is ample evidence that COVID-19 vaccines provide protection against the disease, preventing hospitalizations and deaths. This is inconsistent with the claim that COVID-19 vaccines cause ADE.

Another way to interpret the term “vaccine-mediated viral enhancement”, which isn’t a known scientific concept, is based on the article’s claim that vaccination “makes the virus learn to grow stronger and more durable”, in reference to the emergence of the Delta variant of SARS-CoV-2. However, this variant of the virus was first isolated in India in October 2020, months before the vaccination campaign started, so it’s impossible for vaccination to have caused the Delta variant.

The article also claimed that Geert Vanden Bossche and Luc Montagnier were right in their predictions about COVID-19 vaccines. Vanden Bossche published an open letter claiming that COVID-19 vaccination campaigns would accelerate the emergence of dangerous variants of the virus. But  his hypotheses  weren’t founded on evidence nor were they supported by past experience with other vaccination campaigns, like those for measles and mumps, as explained in this claim review by Health Feedback and this article by McGill University’s Office for Science and Society.

As for Montagnier, he claimed in a video that “the new variants are a production and result from the vaccination” and “the curve of vaccination is followed by the curve of deaths”, referring to ADE. These claims have been addressed in several fact-checks, like this one from PolitiFact and this one by Reuters.

Claim 3 (Unsupported): The low number of COVID-19 cases in Sweden is due to herd immunity from previous infections

The article’s central argument rests on its claim that the lower number of COVID-19 cases in Sweden relative to other countries is explained by herd immunity of the population to COVID-19, stating that “the fact that Sweden has never gotten a Delta wave demonstrates that natural immunity alone would have ended this pandemic”.

The article claimed that since Sweden already achieved herd immunity through infection before the vaccines, vaccination doesn’t explain the low number of COVID-19 cases in the country. The article went as far as to claim that the incidence rate of COVID-19 would be still the same even if Sweden’s population hadn’t been vaccinated.

Apart from the inaccurate claim that “has never gotten a Delta wave”, as explained earlier Horowitz provided no evidence to support his assumption that Sweden already achieved infection-induced herd immunity, or “natural immunity” as the article termed it.

The article by The Blaze indicated that Sweden started its COVID-19 vaccination campaign later than other countries such as the U.S. or the U.K. However, current vaccine coverage in the country is similar to those countries. According to data collected by Reuters, Sweden has administered more than 15,250,000 doses of COVID-19 vaccines as of 23 November 2021.

According to Our World in Data, 69% of Sweden’s population has already been fully vaccinated against COVID-19. This figure is similar to those in countries such as the U.K. (68%) or Germany (68%), and higher than that of the U.S. (58%) or the average for European countries (57%) (Figure 3).

Figure 3. Proportion of fully vaccinated people in different countries. Data retrieved on 26 November 2021. Source: Our World in Data.

Current data suggest that vaccines reduce COVID-19 transmission[1], even for the Delta variant[2]. Therefore, since vaccines reduce the transmission of COVID-19, we cannot dismiss their contribution to Sweden’s currently low number of cases, as Horowitz did.

Claim 4 (Misleading): A study carried out in Sweden “found no effectiveness from the Pfizer shot after 6-7 months”

The article cited a study carried out in Sweden examining the effectiveness of COVID-19 vaccines over nine months[3]. The article claimed that “[the study] found that after 6-7 months, ‘no effectiveness could be detected’ from the Pfizer shot” and that “for some older adults, the shots are as much as -77% effective” after seven months.

However, this is an incomplete and misleading interpretation of the study’s results. While the study reported that “from day 211 and onwards no effectiveness could be detected”, this finding was with regards to vaccine effectiveness against symptomatic infection, as shown in the data from the study’s Supplemental Table 4). The study found that vaccine effectiveness against COVID-19 hospitalization and death remained high even nine months after vaccination, with over 50% of effectiveness against severe illness for all groups in the study (as shown in its Supplemental Table 5), and the authors concluded that their findings “[strengthen] the evidence-based rationale for administration of a third booster dose”.

In conclusion, the article didn’t provide evidence that infection-induced immunity is the cause of the low number of cases in Sweden. Given that vaccine coverage in the country is nearly 70%, which is similar to other countries like the U.K. or Germany, vaccines can’t be ruled out as the cause of the reduction in Sweden’s COVID-19 cases. There’s also no evidence supporting the article’s claim that vaccines produce variants that are more dangerous.


Science Feedback is a non-partisan, non-profit organization dedicated to science education. Our reviews are crowdsourced directly from a community of scientists with relevant expertise. We strive to explain whether and why information is or is not consistent with the science and to help readers know which news to trust.
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