The post’s author claims that New Zealand is recording a record number of hospitalizations due to severe acute respiratory infections this winter season, allegedly more than twice the peak during the COVID-19 pandemic.
At the same time, it is ironically asked why there is no longer talk about isolating people or other restrictions during the current situation, which during the pandemic were based on the goal of not overloading the healthcare system.
It is further reminded that New Zealand and Australia applied very strict border and movement restrictions at the beginning of the pandemic.
It is claimed that this way the countries avoided early COVID-19 variants for some time, vaccinated more than 90% of the population, and only opened borders more widely after the spread of Omicron variants.
These facts are presented in the post as a basis for the hint that the current increase in respiratory infections could be a consequence of earlier pandemic policies and the high scale of vaccination.
The author also claims that there are studies allegedly showing that vaccination against some respiratory viruses may increase susceptibility to other acute respiratory infections.
Separately, a study published in the journal “Nature” involving 1,745 Swiss healthcare workers is cited. The post states that the more COVID-19 vaccine doses the study participants received, the more often they experienced flu-like respiratory infections and the more workdays they missed due to illness.
It is emphasized that the frequency of such illnesses among workers who received four doses was allegedly up to 70% higher than among the unvaccinated, and the number of sick leave days was up to one and a half times higher.
Thus, from several separate data points, a broader claim is constructed that COVID-19 vaccination may have weakened protection against other respiratory infections, and the current epidemiological situation in New Zealand is allegedly a consequence of this.
However, there is no reliable scientific evidence that a causal link exists between COVID-19 vaccination and the current rise in hospitalizations in New Zealand.
What is happening in New Zealand?
As reported by the news portal 1news.co.nz, New Zealand is currently facing an extremely intense flu season.
In Auckland, the number of flu-related hospitalizations has reached the highest level in a decade, and nationwide infection rates are the highest in four years and continue to rise. According to Dale Bramley, head of Health NZ, the greatest pressure on the health system currently comes from influenza type A, but respiratory syncytial virus (RSV), other cold viruses, and COVID-19 also contribute to the overall morbidity.
Increased morbidity is also reflected in data from the medical assistance line “Healthline”: the number of calls in a week was about 20% higher than in July, so the service had to increase capacity and the number of on-call nurses and paramedics.
Almost a third of callers were calling about children under five years old. Michael Baker, professor of public health at Otago University, warned that the country’s health system is already under heavy strain, and once the epidemic curve peaks, the ability to quickly change its trajectory is limited.
However, contrary to claims in the “Facebook” post, scientists do not link record morbidity rates with COVID-19 vaccines.
Why has this situation developed?
The main reason for the current health system overload is a late and sudden surge in the flu season. Most cases are caused by influenza type A, but respiratory syncytial virus (RSV), other cold viruses, and COVID-19 are also widely circulating.
Michael Baker, professor of public health at Otago University, emphasizes that the problem is deepened not only by the spread of viruses themselves but also by a delayed response.
According to him, when the epidemic curve is already rising rapidly and the health system begins to struggle due to increased patient flow, it becomes much harder to change the situation’s trajectory.
The professor says he misses more prompt measures – clearer recommendations to wear masks indoors and extra caution in higher-risk places, such as public transport or healthcare facility waiting rooms.
According to M. Baker, workplace culture also contributes to the spread of infections. Employers could more actively encourage sick employees not to come to work and, when possible, provide conditions for remote work.
The professor also points out that New Zealand lacks a tiered warning system that clearly shows the population the current level of respiratory infection risk in the community.
Such systems operate in some other countries, but their implementation, according to him, requires not only technical readiness and cooperation with communities but also political and health system leadership will.
Are the numbers really that high?
The claim that the current level of severe acute respiratory infection (SARI) hospitalizations in New Zealand is more than twice the COVID-19 pandemic peaks does not correspond to officially published data.
For the week ending August 16, “PHF Science” indeed recorded a record total SARI hospitalization rate since monitoring began in 2012. According to data from four Auckland region hospitals participating in the monitoring system, 177 patients were hospitalized in a week, compared to 125 the previous week.
However, this record by itself does not mean that current rates are more than twice the highs during the pandemic period.
Public health physician expert Hannah Cooper points out that flu-caused SARI hospitalization rates are currently close to the high levels of 2022. In other words, official data show a similar scale, not more than double the rate.
It is also important that SARI monitoring is not nationwide hospitalization statistics. It is conducted in four hospitals in Auckland and Counties Manukau and covers about 1.2 million people, or roughly 23% of New Zealand’s population. Therefore, these data cannot be directly generalized as nationwide morbidity or hospitalization rates.
What about COVID vaccines?
The “Facebook” post selectively and out of context presents excerpts from several scientific studies, distorting their meaning to make it seem that the current surge in respiratory infections in New Zealand could have been caused by strict COVID-19 control or mass vaccination during the pandemic.
However, the impression of such a causal link created in the post is not supported by scientific data.
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Preliminary epidemiological data show a completely different main cause – the currently dominant influenza A/H3 subclade K virus in the country. This is the same variant that was already associated with an intense flu season in the Northern Hemisphere.
It has evolved significantly away from the A/H3 viruses circulating in recent seasons, so the natural immunity formed in the population against it is limited. This creates more favorable conditions for the virus to spread rapidly.
This strongly contradicts the connection suggested in the post with New Zealand’s exceptional pandemic policy. K subclade viruses spread and established themselves in countries that never applied such strict restrictions as New Zealand.
The first sequence of this subclade in the GISAID database was recorded on June 23, 2025, in New York, later the virus was detected in Wisconsin and Michigan, and phylogeographic analysis shows that it most likely entered Australia from the USA and only later reached New Zealand.
By the end of November 2025, K subclade viruses had already been detected in at least 34 countries – the USA, thirteen Western European countries, as well as in Asia, Africa, and the Middle East.
In other words, this flu variant spread widely regardless of what COVID-19 restrictions or vaccination strategies were previously applied in specific countries.
This is incompatible with the idea suggested in the post that the current surge in morbidity in New Zealand could have been caused by its earlier isolation policy or vaccination levels.
What did the Swiss study reveal?
The post presents a Swiss healthcare worker study as one of the main arguments, allegedly confirming that COVID-19 vaccination weakens immunity and increases susceptibility to other infections. However, the study itself does not make such a conclusion.
First of all, it did not assess the immune system status at all. The researchers did not conduct cellular immunity or other mechanism studies and clearly stated in some parts that they did not have the necessary biological samples for that.
Therefore, the authors discuss possible biological explanations only as hypotheses, not as mechanisms confirmed by the study. In other words, the claim that COVID-19 vaccines “weaken immunity” was neither directly measured nor proven by this study’s data.
It is also important what the researchers actually considered the main outcome. They evaluated not all infectious diseases and not even laboratory-confirmed flu cases, but episodes of flu-like symptoms.
This is especially important when interpreting the results. During the study period in Switzerland, among people tested for flu-like symptoms, a similar proportion tested positive for both SARS-CoV-2 and influenza. Moreover, the authors noted that participants who received more vaccine doses had less often had COVID-19 and less often had infection-indicating anti-N antibodies.
Therefore, one possible explanation for the observed statistical association, discussed by the authors themselves, is lower immunity from prior infection, not a general immune system weakening caused by vaccination.
Another important detail is that the association depended more on how recently a person was vaccinated than on the total number of doses received. When the time since the last vaccination was included in the statistical model, the association with the number of doses disappeared, while a stronger association remained with recent vaccination. The authors themselves interpreted this as a possibly temporary association that weakens over time, not a long-term “depletion” of immunity.
Therefore, the results of this study cannot be directly applied to the current flu epidemic in New Zealand. The study covered the 2023–2024 period, while the current surge in morbidity in New Zealand is recorded in 2026.
Moreover, among the most hospitalized groups are young children, some of whom were not vaccinated against COVID-19 at all. Thus, the study does not confirm the claim that the current flu outbreak was caused by a long-term effect of COVID-19 vaccination on the immune system.
They studied healthcare workers
It is also important that the study authors themselves did not raise the question of whether COVID-19 vaccines “weaken immunity.” Their study goal was much narrower – to assess whether regular revaccination against SARS-CoV-2 provides additional benefits to low-risk healthcare workers after the pandemic phase.
The authors concluded that in their studied group, revaccination was not associated with measurable additional protection against flu-like illnesses and might be temporarily associated with a higher likelihood of symptomatic infection and missed workdays due to illness.
However, this is presented as a limited statistical association, not as proof that vaccines damage or weaken the immune system over time.
The scientists themselves emphasized that further studies and more detailed evaluation of possible immunological mechanisms are needed to confirm the results.
Thus, the study’s conclusion is narrow and conditional – it relates to the benefit of post-pandemic revaccination in a specific group of healthy, mostly middle-aged healthcare workers, not to the overall effect of COVID-19 vaccines on human immunity.
The scientists themselves emphasized that further studies and more detailed evaluation of possible immunological mechanisms are needed to confirm the results.
Thus, the study’s conclusion is narrow and conditional – it relates to the benefit of post-pandemic revaccination in a specific group of healthy, mostly middle-aged healthcare workers, not to the overall effect of COVID-19 vaccines on human immunity.
15min verdict: lacking context. New Zealand is indeed experiencing an extremely intense flu season and record SARI hospitalization rates in monitored Auckland hospitals, but there is no basis to claim that they are more than twice the COVID-19 pandemic peaks.
More importantly, there is no scientific data linking the current surge in morbidity with previous COVID-19 restrictions or vaccination: the main factor is considered the widely spread influenza A(H3N2) K subclade virus worldwide.
The Swiss study cited in the post also does not prove that COVID-19 vaccines weaken immunity – immunity was not measured in it, and the authors described a limited and possibly temporary statistical association in a specific healthcare worker group.
Publication prepared by 15min in cooperation with Meta, aiming to stop the spread of misleading news on social media. More about the program and its rules – here.
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