Five Years of COVID-19: Reflections from the Society for Virology on the Pandemic Response in Germany

Five Years of COVID-19: Reflections from the Society for Virology on the Pandemic Response in Germany

Five years after the onset of the COVID-19 pandemic, the global threat posed by a novel airborne virus has largely subsided. However, in public discourse, scientific facts and the context of past decisions are increasingly being distorted. This particularly affects the evaluation of public health interventions and vaccination campaigns.

A growing disregard for scientific standards in parts of the public discussion, along with the politicization of pandemic-related commentary, has undermined public trust in science-based policymaking. The Society for Virology (GfV) observes this trend with concern, as it hampers objective, evidence-based retrospective analysis of the pandemic.

A thorough scientific review of the effectiveness of pandemic control measures has been set in motion, a process welcomed by the GfV. Multiple disciplines, including virology, epidemiology, and public health, are contributing to this evaluation. Scientific evidence must serve as the foundation for any political assessment. Accordingly, the GfV seeks to highlight and contextualize several key insights, which, have often been misrepresented or misunderstood in public debates, thereby negatively influencing societal perceptions.

Initial Assessment of COVID-19 Threat

At the onset of the COVID-19 pandemic, assessments of the new virus's potential danger were necessarily preliminary—and in some cases, prematurely reassuring. A key element in gauging the threat was estimating mortality, yet the concept of “mortality” itself proved to be a source of confusion during public and scientific discourse.

Two main metrics are used to describe mortality in infectious disease outbreaks: the infection fatality rate (IFR) and the case fatality rate (CFR). The IFR reflects the proportion of all infected individuals (including undiagnosed cases) who die from the disease and is the most meaningful measure when estimating the overall severity of an outbreak across a population. However, determining the IFR requires accounting for unreported and asymptomatic infections—something that cannot be directly inferred from routine surveillance data.

In contrast, the CFR is calculated from reported cases only. It reflects the proportion of confirmed cases that result in death and is highly sensitive to testing practices and case detection rates. In the early stages of a pandemic, when testing is limited and many infections go undetected, the CFR tends to overestimate mortality. Despite these limitations, the CFR was often used in early comparisons—such as between COVID-19 and seasonal influenza—leading to misleading conclusions. For instance, while seasonal influenza typically has a CFR around 0.1%, early estimates of COVID-19's CFR were substantially higher—2.4% in Europe and 3.4% globally as of March 2020 (Robert Koch Institute, 2020a).

To estimate the more relevant IFR, researchers rely on statistical modeling. In modern infectious disease epidemiology, such modeling incorporates seroprevalence studies, demographic data, and assumptions about underreporting. While these models are foundational for sound risk assessment, they were sometimes dismissed in public debate as speculative or unrealistic, calling into question the scientific arguments and authority in the assessing the severity of the pandemic.

Nevertheless, robust modeling estimates of COVID-19’s IFR became available early in the pandemic. Studies from the first wave suggested an IFR of 0.7% to 1% (Dorigatti et al., 2020; Verity et al., 2020). By mid-2020, comprehensive international analyses, such as those by O’Driscoll et al. (2021), placed Germany’s IFR at just under 1%. In Spain, large-scale antibody studies produced directly observed IFR estimates in a similar range, confirming the reliability of cross-country modeling (Pastor-Barriuso et al., 2020). Further comparisons with direct studies from other countries also validated these early estimates (Levin et al., 2020).

In contrast, significantly lower IFR estimates were published by Ioannidis (2021), who reported values of 0.26% and 0.28% for Germany. However, these figures were derived from small, early seroprevalence studies—one in Heinsberg (Streeck et al., 2020) and another among company employees in Frankfurt (Krähling et al., 2020). These studies were not representative of the general population and were based on minimal sample sizes (7 deaths in Heinsberg; 5 positive cases in Frankfurt), limiting their reliability for broader extrapolation.

More recent studies continue to support the earlier estimates. For example, a newly published study from Austria confirmed an IFR of 0.5% to 1% during the 2020/2021 winter wave (Riedmann et al., 2025), consistent with estimates for England over the entire year of 2020 (Eales et al., 2023). Taken together, there is now a strong scientific consensus that initial estimates of COVID-19’s severity were broadly accurate. In comparison, seasonal influenza has an IFR typically below 0.1%—estimated at 0.04% to 0.08% in the U.S. (Levin et al., 2020). This implies that, in the early pandemic phase, COVID-19 was roughly 10 to 20 times more lethal than seasonal influenza, with a conservative assumption of 0.5% to 1% IFR for COVID-19 versus 0.05% for influenza.

Despite this, public messaging in early 2020 frequently equated COVID-19 with seasonal flu, thereby downplaying the potential threat to the population and the healthcare system. In hindsight, this comparison underestimated the seriousness of the situation. It is only through widespread immunity—achieved via vaccination and prior infection—that the individual and societal risk has since declined, with most people now protected against severe outcomes (Meslé et al., 2024).

Herd Immunity Through Natural Infection as a Pandemic Strategy

In the early stages of the pandemic, some countries conducted studies to determine whether a level of pre-existing population immunity against SARS-CoV-2 might already exist. However, these investigations often failed to produce the hoped-for insights. One prominent example is the Heinsberg study, which was widely interpreted in public discourse as indicating a high level of immunity. Yet the authors themselves acknowledged that the study did not provide a representative estimate of antibody prevalence for Germany as a whole (Streeck et al., 2020). The infection fatality rate (IFR) of 0.35% reported in the study was likewise not representative, as the outbreak it analyzed stemmed from a carnival event where elderly and high-risk individuals were likely underrepresented. In that context, the IFR findings of the study did not warrant reassuring interpretations. Furthermore, the estimated regional immunity level of approximately 15% offered no scientific justification for assuming population-level protection, nor did it support calls for an end to infection control measures.

In hindsight, public proposals advocating for allowing infections to spread among younger adults and children—as a path to achieving herd immunity—must be regarded as clear misjudgments (Great Barrington Declaration, 2020). While it is valid to acknowledge the psychological, social, and economic burdens imposed by contact restrictions, the herd immunity proposals were based on a flawed assumption: that a single infection with SARS-CoV-2 would confer long-lasting immunity sufficient to block onward transmission to vulnerable individuals. Reality has shown otherwise. Despite repeated infections and widespread vaccination, SARS-CoV-2 continues to circulate globally. Had contact reduction measures been lifted early as proposed, this would have resulted in sustained exposure of vulnerable individuals across all age groups, with potentially devastating consequences.

Targeted Protection of High-Risk Groups

Early on, it was evident that elderly individuals and those with comorbidities (e.g., cardiovascular or metabolic diseases, genetic disorders, cancer, or immunodeficiencies) were at particularly high risk of severe COVID-19 (Vygen-Bonnet et al. 2021a). The proposed herd immunity strategies would have exposed these groups to potentially fatal threats. Advocates of herd immunity argued for targeted protection of these vulnerable individuals while letting the infection spread in the general population.

However, according to an analysis by the Standing Committee on Vaccination (STIKO), approximately 36.5 million people in Germany fall into these high-risk categories. No practical or feasible strategy was ever presented for how such a large portion of the population could be specifically shielded. As a result, this argument implicitly endangered and marginalized vulnerable societal groups while ignoring the reality that, before vaccines became available, reliable protection of at-risk individuals could not be achieved without a broader reduction of transmission within the general population.

Selective protection of the elderly was also proposed as a variant of this strategy. Yet this approach proved unfeasible in practice. For example, in Sweden, the first wave of the pandemic resulted in a COVID-19 mortality rate approximately ten times higher than in other Scandinavian countries. This was largely attributable to outbreaks among the elderly, including those in long-term care facilities (Juul et al. 2022). Scientific evaluations of these outcomes show that the strategy of selectively protecting nursing home residents was ineffective (Bjoerkheim and Tabarrok 2022).

At the time when broad contact reduction measures were being implemented, there was also no nationwide testing infrastructure in place, which became a part of the pandemic response strategy only at later points. Moreover, alongside the known risk groups, an additional population segment with a very different risk profile began to emerge: individuals vulnerable to Long COVID. Between 2020 and 2023, approximately 6% of adults and 1% of children who had experienced symptomatic COVID-19 went on to develop persistent, often debilitating symptoms. If a herd immunity strategy had been pursued, the result would likely have been a substantial burden of long-term illness across society (Al-Aly et al. 2024; Cai et al. 2024).

Policy Decisions on School Closures

Public debate about the proportionality of school closures is often marked by oversimplification and the retrospective omission of important medical and political context. Virologists and infectious disease epidemiologists emphasized early on the importance of interdisciplinary perspectives in evaluating the potential negative effects of school closures (GfV 2020). Claims that virology marginalized other areas of expertise are not supported by the record, nor were such intentions ever expressed by virologists. Multiple contrary examples exist, including position papers (GfV 2020; Leopoldina 2020) and membership lists of advisory committees (State of North Rhine-Westphalia 2020).

Much of the retrospective criticism ignores key considerations present at the beginning of the pandemic, when protecting children from the unknown direct and indirect consequences of infection was a primary concern. Among these was the risk of rare but serious post-infectious complications in children (Verdoni et al. 2020). Two distinct issues were often conflated in the public debate: while children were clearly at lower risk of severe illness, this did not imply that they were less likely to become infected or contribute to transmission (Robert Koch Institute 2020b). A major concern at the time was the potential introduction of infections into households via schools. Early school-based studies, including those conducted in Germany, provided limited information due to low community incidence at the time (autumn 2020) and often failed to assess infection prevalence in the surrounding population using the same methodology, limiting their overall usefulness.

In contrast, comprehensive data from the United Kingdom—such as those from the Office for National Statistics and the REACT-1 study—showed that infection rates among children were comparable to those of adults (Elliott et al. 2023). Schools could therefore not be assumed to be low-transmission settings. Political decisions required balancing risks across various areas of public life, including workplaces, schools, retail, hospitality, and religious institutions.

Subsequent scientific analyses confirmed that school closures significantly contributed to reducing overall infection rates, hospitalizations, and deaths (Murphy et al. 2023). At the same time, the significant social and educational harms associated with closures raised the question of whether more targeted interventions in other sectors could have substituted for prolonged school shutdowns. In August 2020, the Society for Virology issued a statement advocating for strategies to avoid further school closures (GfV 2020). In contrast to schools, workplaces in Germany were not widely discussed as sources of transmission, unlike in other countries—a discrepancy repeatedly highlighted by GfV members.

Evaluating the Benefits and Risks of COVID-19 Vaccines

The rapid development of COVID-19 vaccines and their high efficacy against symptomatic disease were instrumental in overcoming the pandemic. This achievement was made possible only by decades of basic research, for example on stabilizing viral surface proteins (Sanders and Moore 2021) and viral vector platforms. The BioNTech mRNA vaccine (Comirnaty) prevented 19 out of 20 cases of symptomatic COVID-19 in the early months after vaccination (Vygen-Bonnet et al. 2021a). According to WHO estimates, between 2020 and March 2023, approximately 1.6 million deaths were prevented in Europe alone as a result of COVID-19 vaccination (Meslé et al. 2024). No signals for serious adverse events were detected in the Comirnaty phase 3 trials. Side effects occurring in more than 0.1% of recipients during the first few weeks after vaccination would have been identified with greater than 95% certainty in these studies (Vygen-Bonnet et al. 2021a). With an IFR of about 1%, the risk-benefit balance clearly favors vaccination. After vaccine approval, safety monitoring continued through established pharmacovigilance systems. The Paul Ehrlich Institute maintains a comprehensive database of suspected adverse events and investigates all serious cases in collaboration with treating physicians. It is important to distinguish between two stages of vaccine safety monitoring, which are often conflated in public discourse. Initial signals are generated through spontaneous reports, prompting international data reviews, physician advisories, and focused follow-up studies. These processes are designed to rigorously evaluate the validity of early risk signals.<br>

After vaccine approval, safety monitoring continued through established pharmacovigilance systems. The Paul Ehrlich Institute maintains a comprehensive database of suspected adverse events and investigates all serious cases in collaboration with treating physicians. It is important to distinguish between two stages of vaccine safety monitoring, which are often conflated in public discourse. Initial signals are generated through spontaneous reports, prompting international data reviews, physician advisories, and focused follow-up studies. These processes are designed to rigorously evaluate the validity of early risk signals.
Claims that underreporting in any single country—such as Germany—could cause serious side effects to go unnoticed are fundamentally incorrect. The detection of very rare cases of cerebral venous sinus thrombosis associated with AstraZeneca’s vaccine (Vaxzevria), occurring in just 1–3 per 100,000 vaccinated individuals aged 20–59, demonstrates the effectiveness of this system (Vygen-Bonnet et al. 2021c; Pottegård et al. 2021). This finding led to the suspension of Vaxzevria use in the affected age group in Germany.
Speculative claims that mRNA vaccines could cause genetic alterations or cancer due to residual DNA fragments from the manufacturing process are not supported by experimental or clinical data. For over 20 years, plasmid DNA has been administered in milligram quantities during clinical trials for DNA vaccines and gene therapies (Wang and Yuan, 2024). Animal studies show that the risk of chromosomal integration is lower than the risk of spontaneous mutations (Ledwith et al. 2000), and no tumor cases have been reported in human trials. In fact, based on a phase 3 trial (Khobragade et al. 2022), even a DNA vaccine ZyCoV-D for SARS-CoV-2 was authorized in India for defined indications in 2021.
Concerns about elevated DNA residues in mRNA vaccine batches are largely attributable to technical errors in distinguishing DNA from RNA during measurement (Kaiser et al. 2024). Sensitive qPCR assays found DNA residues in Comirnaty to be between 0.2 and 2.2 ng per dose (Speicher et al. 2023), which is 1,000 to 10,000 times lower than the doses used in DNA vaccines and considered safe.

Effectiveness of COVID-19 Vaccines Against Infection and Disease

In Germany, public understanding of the effectiveness of COVID-19 vaccines has been marked by numerous misconceptions. A common retrospective claim is that, contrary to initial expectations, the vaccines did not prevent transmission. In fact, scientific evaluation of vaccine effectiveness distinguishes between three forms of protection: protection against infection, protection against disease, and reduction of onward transmission by vaccinated individuals.
The mRNA vaccines developed by BioNTech and Moderna were specifically designed to prevent severe COVID-19 illness—hence the designation “COVID-19 vaccines.” However, initial application data showed that they also provided very high protection against infection itself, with effectiveness rates of 94.1% to 95% (Vygen-Bonnet et al. 2021b). This includes a protection from onward transmission, because the person who is not infected will also not transmit the virus. With the emergence of the Delta variant, protection against transmission decreased, but remained clearly measurable (Chemaitelly et al. 2021). It was only with the rise of the Omicron variant in spring 2022 that much of the vaccine-induced protection against transmission was lost—although strong protection against severe disease persisted (Altarawneh et al. 2022).
By that time, however, public and political debates about vaccine mandates or “3G”/“2G” access rules had largely subsided. Those debates took place mainly in autumn 2021, when the Delta variant was still dominant and vaccine-conferred protection against transmission was still demonstrable.
Oversimplified political and media narratives have contributed to confusion in the public discourse. The often-cited statement by then–Health Minister Jens Spahn about a “pandemic of the unvaccinated” has frequently been criticized out of context. Yet at the time it was made, it had a clear scientific foundation: real-world data from the Robert Koch Institute in autumn 2021 attributed nine out of ten COVID-19 transmissions in Germany to cases involving at least one unvaccinated individual (Maier et al. 2022).
Furthermore, during this period, there was a clear relationship between vaccination rates and the incidence of severe COVID-19 cases at the federal state level. Regions with lower vaccination coverage experienced significant hospital overburden, driven in part by the high pathogenicity of the Delta variant. Neither the Robert Koch Institute nor GfV members ever claimed that unvaccinated individuals alone were responsible for transmission. Nonetheless, the urgent call for widespread vaccination uptake was based on robust scientific evidence and sound public health reasoning.

Throughout the pandemic, public doubts were repeatedly voiced regarding the existence of Long COVID. These doubts are not supported by the scientific evidence. Leading research groups have shown that, between 2020 and the end of 2023, around 6% of individuals with symptomatic COVID-19 continued to experience symptoms for at least three months. These symptoms typically fall into three major categories: persistent fatigue and pain; cognitive impairment; and ongoing respiratory or systemic symptoms attributable to COVID-19 (Al-Aly et al. 2024).
Importantly, Long COVID can also occur after asymptomatic or mild cases. In the countries evaluated—primarily high-income Western nations—6% of all adults and 1% of all children experienced Long COVID at least once between 2020 and 2023.
Unlike acute severe COVID-19, which disproportionately affects older adults and those with preexisting conditions, Long COVID does not follow the same risk profile. It thus constitutes a separate and broader public health challenge. Notably, full vaccination reduces the risk of developing Long COVID by approximately 40% on average (Al-Aly et al. 2024).
Had a herd immunity strategy targeting “low-risk” groups been implemented before the vaccination campaign, it would almost certainly have resulted in a significantly higher number of Long COVID cases across the population.

Retrospective Scientific Evaluation of the  Effectiveness of Non-Pharmaceutical Interventions (NPIs)

The retrospective evaluation of NPIs falls within the domain of infectious disease sciences, including virology. Other academic disciplines, which possess relevant expertise regarding the societal burdens and costs of these measures, have made their own contributions to the discussion—and the GfV refers to their assessments where appropriate. In public debates surrounding the effectiveness of NPIs, overly simplified claims have often been made—sometimes based on individual studies of insufficient design or methodological rigor. The core challenge in assessing the effectiveness of NPIs lies in isolating the effects of individual measures while controlling for confounding variables, as well as interpreting their impact in proper temporal and causal relation to the trajectory of incidence.

To assess the effectiveness of NPIs, GfV relies on publicly accessible evidence that incorporates both quality assessments and weightings of the available studies, alongside summaries of high-quality research. One such key resource is the set of evidence syntheses published by the UK’s Royal Society in autumn 2023. These reviews incorporated global literature up to the end of 2021 and focused on the period prior to the lifting of most NPIs in many industrialized nations, including Germany. After that point, cross-country comparisons became increasingly difficult due to varied national responses to the emerging Omicron variant and differing vaccination coverage. In the view of the GfV, the Royal Society reviews therefore provide the most suitable basis for assessing the effectiveness of NPIs.
The primary criterion in most categories of analysis was the effect of a given measure on epidemiological indicators—such as incidence, reproduction number (R), hospital admissions, or deaths. The findings of these reviews are complex and can only be summarized selectively here.

The most effective NPIs were restrictions on mobility and gatherings, with their impact increasing as group sizes decreased (Murphy et al. 2023). Visitor restrictions and especially continuous cohorting of caregivers with residents in long-term care facilities were effective in protecting these vulnerable groups—but only when implemented alongside broader infection control measures. It should be noted, however, that only a small fraction of the overall vulnerable population (e.g., the very elderly, or individuals with certain high-risk disabilities such as trisomies) resides in institutional care.

School closures had a demonstrable impact on transmission, hospital admissions, and mortality in surrounding communities (Murphy et al. 2023). Measures implemented during in-person schooling—such as mask mandates, physical distancing, and cohort (shift) systems—reduced transmission both within schools and in the wider community. Most studies showed an increase in incidence following the reopening of schools after closures (Murphy et al. 2023).

Reductions in work-related mobility—through workplace closures, formation of small work groups, and remote work—had a clear and pronounced effect, similar in magnitude to that observed with school closures (Murphy et al. 2023).

Closures of bars and restaurants also contributed to reduced transmission, hospitalizations, and deaths in surrounding communities. Even partial restrictions—such as shorter opening hours, reduced seating capacity, or alcohol bans—had measurable effects (Murphy et al. 2023).

The majority of studies on testing, contact tracing, and test-based isolation found a clear and measurable effect in reducing disease incidence (Littlecott et al. 2023). Of particular note is a randomized controlled trial showing that daily testing of contacts was as effective for infection control as a 10-day quarantine. These findings offer valuable perspectives for maintaining school operations. However, it must be noted that widespread testing infrastructure in Germany was only available from 2021 onward.

The Royal Society’s synthesis also found that mask use had a significant effect on reducing transmission, with higher-quality masks and mandatory usage proving more effective than simple cloth masks or voluntary use (Boulos et al. 2023).

For general environmental hygiene measures—which in Germany were widely implemented under the term “hygiene concepts”—the evidence base was weaker. The authors of the synthesis note, however, that such effects are often difficult to capture using existing study designs (Madhusudanan et al. 2023). Finally, border closures were found to have limited effectiveness in preventing viral entry based on the studies available (Grépin et al. 2023).

This statement addresses only a selection of key issues that arose during the pandemic. The Society for Virology strongly advocates for a comprehensive, critical, and interdisciplinary review of all major aspects of the pandemic response.

Signed by the Board and Advisory Council of the Society of Virology

Representing over 1,300 virologists from Germany, Austria, and Switzerland

PDF version of the statement

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