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Between 1 January and 31 December 2023, a total of 19,955 dengue fever cases were reported, including 8,275 confirmed cases, 11,659 probable cases, and 21 suspected cases. Of the 19,934 confirmed and probable cases, there were 14,585 indigenous cases, 3,632 domestic imported cases, 1,579 overseas imported cases, and 138 other cases (including 101 cases with unclear definitions, 30 cases with unknown imports from overseas, and 7 cases from Hong Kong and Taiwan of China). There was one death among domestic imported cases. The time intervals from onset to diagnosis for indigenous cases, domestic imported cases, and overseas imported cases were 3, 4, and 3 days, respectively.

Descriptive study of indigenous dengue cases

Temporal distribution of indigenous dengue cases

Indigenous cases of dengue occurred between June and December. It showed seasonal characteristics, with a peak period from August to October (11,753 cases, 80.6%) and September being the peak month (4,817 cases, 33.0%) (Fig. 1, red colour). The peak period of affected regions (provinces, cities, or counties) was from August to November, with October being the peak month.

Spatial distribution of indigenous dengue cases

A total of 14,585 cases were distributed across 140 counties, 54 cities, 10 provinces (Zhejiang, Fujian, Hubei, Hunan, Guangdong, Guangxi, Hainan, Sichuan and Yunnan provinces, and Chongqing Municipality) in the south of the Yangtze River Basin (Fig. 2). The top three areas with cases at the county level were Ruili City, Dehong Dai and Jingpo Autonomous Prefecture, Yunnan Province (3,828 cases, 26.2%); Jinghong City, Xishuangbanna Dai Autonomous Prefecture, Yunnan Province (3,453 cases, 23.7%); and Mengla County, Xishuangbanna Dai Autonomous Prefecture, Yunnan Province (2,209 cases, 15.1%). There were 10,268 cases in the Yunnan Province, accounting for 70.4% of the cases, which were mainly distributed along the southwest border. Additionally, there were 3,756 cases in Guangdong Province (25.8%), mainly distributed in southern coastal areas, with 45.5% in Guangzhou City.

Spatial distribution of indigenous dengue cases in Chinese mainland, 2023

Monthly spatial emerging of indigenous dengue cases

Indigenous cases emerged from low latitudes along the southwestern border and the southern and southeastern coastal areas to high latitudes in the central region from June to September and mainly emerged from low latitudes subsequently (Fig. 3). In June, five counties were affected in the Yunnan, Guangdong, and Fujian provinces. In July, nine counties were newly affected in the Zhejiang, Fujian, Guangdong, and Yunnan provinces. In August, 22 counties were newly affected in Zhejiang, Fujian, Hubei, Hunan, Guangdong, Hainan, and Yunnan provinces. In September, 55 counties were newly affected in the Zhejiang, Fujian, Hubei, Hunan, Guangdong, Hainan, Sichuan and Yunnan provinces, and Chongqing Municipality. In October, 37 counties were newly affected in the Zhejiang, Fujian, Hubei, Guangdong, Hainan, and Sichuan provinces. In November, 11 counties were newly affected in the Guangdong, Sichuan, and Yunnan provinces. In December, one county was newly affected in Guangdong Province.

Monthly spatial emerging of indigenous dengue cases in Chinese mainland, 2023

Demographic distribution of indigenous dengue cases

The male-to-female ratio of indigenous cases was 1.1:1. The top four age groups with the highest number of indigenous cases were 35–44 years (17.9%), 45–54 years (17.9%), 25–34 years (17.6%), and 55–64 years (16.1%), with a total of 69.5% in the 25–64 age group. The top four occupations with the highest number of indigenous cases were farmer (24.5%), households or the unemployed (18.3%), and businesspeople (10.8%), accounting for 53.6%. See Table 2.

Descriptive study of domestic imported dengue cases

Origins and distributions of domestic imported dengue cases

Among the 3,632 domestic imported cases in Chinese mainland in 2023, 1,112 cases (30.6%) were transmitted between provinces, 1,772 cases (48.8%) were transmitted between different cities within the province, and 748 (20.6%) were transmitted between different counties within the city. A total of 3,632 domestic imported cases from 45 counties, 28 cities, and 10 provinces were imported into 579 counties, 179 cities, and 28 provinces among the 31 provinces in Chinese mainland (except Tianjin Municipality, Heilongjiang Province, and Tibet). The origins were mainly Yunnan, Guangdong, and Fujian provinces. The destinations were mainly located in the Yunnan, Guangdong, Zhejiang, Sichuan, and Hunan provinces.

Flow map of domestic imported dengue cases

Of the domestic imported dengue cases, 3,322 (91.5%), 197 (5.4%), and 94 (2.6%) cases were imported from the Yunnan, Guangdong, and Fujian provinces, respectively. Additionally, 19 cases were imported from Zhejiang, Hubei, Hunan, Guangxi, Hainan and Sichuan provinces, and Chongqing Municipality (Fig. 4A). Overall, 3,322 domestic imported cases from Yunnan Province showed a radial output, with 69.7% imported into local cities or counties in Yunnan Province and 30.3% imported into 27 other provinces, including 19.3% imported into Zhejiang, Guangdong, Sichuan, and Hunan provinces. Of the 197 domestic imported cases from Guangdong Province, 75.6% were imported into local cities or counties within Guangdong Province, and 24.4% were imported into 15 other provinces. Of the 94 domestic imported cases from Fujian Province, 51.1% were imported into local cities or counties within Fujian Province, and 48.9% were imported into 6 other provinces.

Moreover, 2,320, 337, 256, 136, and 125 cases were imported into Yunnan, Guangdong, Zhejiang, Sichuan, and Hunan provinces, respectively (Fig. 4B). A total of 2,320 cases imported into Yunnan Province were from Yunnan Province itself, except for 3 cases. Of the 337 cases imported into Guangdong Province, 50.0% were from Yunnan Province, 44.5% were from Guangdong Province, and the remaining were from Zhejiang, Fujian, Hunan, and Guangxi provinces. Of the 256 cases imported into Zhejiang Province, 86.7% were from Yunnan Province, 9.4% were from Fujian Province, and the remaining were from Guangdong and Sichuan provinces. Of the 136 cases imported into Sichuan Province, 98.5% were from Yunnan Province, and the remaining were from Guangdong Province and Chongqing Municipality. Further, 92.8% of 125 cases imported into Hunan Province were from Yunnan Province, and the remaining were from Guangdong and Fujian provinces.

Flow map of domestic imported dengue cases in Chinese mainland, 2023. A Domestic output flow B Domestic input flow

Demographic distribution of domestic imported dengue cases

The male-to-female ratio of domestic imported cases was 1.2:1. The top four age groups with the highest number of domestic imported domestic cases were 25–34 years (27.6%), 35–44 years (22.1%), 45–54 years (16.0%), and 15–24 years (13.4%), with 79.1% in the 15–54 age group. The four occupations with the highest number of domestic imported cases were farmers (38.2%), households or the unemployed (11.2%), and students (9.8%), accounting for 59.2%. See Table 2.

Descriptive study of overseas imported dengue cases

Temporal distribution of overseas imported dengue cases

Imported cases were reported throughout the year. It showed seasonal characteristics, with a peak period from August to September (1,017 cases; 64.4%) (Fig. 1). The peak period of affected regions (provinces, cities, or counties) was from August to October, with September being the peak month.

Origins and distributions of overseas imported dengue cases

There were 1,579 overseas imported cases from 39 countries and regions, with 1,088 cases from Myanmar (68.9%), 133 cases from Laos (8.4%), and 114 cases from Thailand (7.2%) imported into 255 counties, 125 cities, and 22 provinces. Overseas imported cases were clustered along the southwestern border of Yunnan Province (adjacent to Myanmar, Laos, and Vietnam), the coasts of Guangdong and Fujian provinces, and central Zhejiang Province. The three provinces with the highest number of cases were Yunnan Province (1,175 cases, 74.4%), Guangdong Province (124 cases, 7.9%), and Zhejiang Province (88 cases, 5.6%). Among them, 915 cases (57.9%) were distributed in the Xishuangbanna Dai Autonomous Prefecture on the southwestern border of Yunnan Province.

Sankey diagram of overseas imported dengue cases

This Sankey diagram showed that how overseas imported cases flowed from overseas countries to the provinces in Chinese mainland. It showed not only the numbers of cases (different width) but also the distributions (different colors) (Fig. 5).

Sankey diagram of overseas imported dengue cases in Chinese mainland, 2023

Of the 1,088 cases from Myanmar, 97.4% were imported into Yunnan Province, and the remaining were imported into nine other provinces. Of the 133 cases from Laos, 68.4% were imported into Yunnan Province, and the others were imported into 12 other provinces. In total, 38.6% and 22.8% of the 114 cases from Thailand were imported into Guangdong and Zhejiang provinces, respectively, and the others were imported into another 12 provinces.

Of the 1,175 cases imported into Yunnan Province, 91.1% were from Myanmar, and the remaining were from six countries and regions. A total of 124 cases were imported into Guangdong Province from 24 countries and regions, including Thailand and Malaysia. Additionally, 44 cases were imported into Zhejiang Province from 22 countries and regions, including Thailand and Laos.

Demographic distribution analyses of overseas imported dengue cases

The male-to-female ratio of imported cases was 1.7:1. The four age groups with the highest number of overseas imported cases were 35–44 years (26.2%), 25–34 years (25.9%), 45–54 years (18.2%), and 55–64 years (10.9%), with 80.9% in the 25–64 age group. The two occupations with the highest number of overseas imported cases were farmers (49.3%) and businesspeople (11.9%), accounting for 61.2%. See Table 2.

Vaccines today prevent or significantly reduce the impact of around 30 dangerous and potentially life-threatening diseases. Consistent vaccination programs have been crucial in ensuring that most of these illnesses no longer pose a public health threat, as a large portion of the population is immunized before encountering the infections. Vaccines and vaccination programs thus represent one of the greatest success stories in infectious disease prevention.

However, few medical interventions spark as much skepticism in certain populations as vaccination. The specific effects of these doubts — ranging from hesitancy about particular vaccines to outright refusal — are hard to quantify, especially because other factors can also lead to low vaccination rates. For example, conducting vaccination campaigns in crisis or war zones remains challenging, even when sufficient vaccine supplies exist and most eligible people want to be vaccinated.

Threat to Infectious Disease Control

It is well-established that diseases such as polio and measles could be eradicated through consistent immunization of a sufficiently large segment of the population. Likewise, severe illness among especially vulnerable individuals — who cannot be vaccinated due to medical reasons — can be prevented through herd immunity, thereby reducing individual suffering. Yet, those with skeptical or anti-vaccine views often ignore or deny these facts. Instead, they argue that vaccination is a personal decision to be made solely between the individual and their healthcare provider. In this view, national vaccination plans designed to protect both individuals and the community are given lesser importance.

Not Without Consequences

In 2019, before the COVID-19 pandemic brought renewed focus to vaccination, the World Health Organization (WHO) identified vaccine skepticism as one of the top 10 global health threats. The WHO defines vaccine skepticism as the “delayed acceptance or refusal of vaccines despite the availability of vaccination services.”

Experts at WHO are particularly concerned that such skepticism threatens to reverse significant progress made in recent decades against vaccine-preventable diseases. Despite numerous efforts to educate the public objectively about vaccines and increase acceptance, vaccine-skeptical views continue to gain influence in societal discourse and among decision-makers worldwide.

Social media plays a key role in this trend. Misinformation can spread rapidly and often goes uncorrected, amplifying fears and bringing latent anxieties to the surface. These platforms act as multipliers: Individuals who have long harbored vaccine skepticism find their concerns reinforced by reports of potential dangers from supposedly insufficiently tested new vaccines, while those previously neutral or positive about vaccination become uncertain. Both groups share their fears and false beliefs, fueling further spread within networks of similarly doubtful people.

COVID-19 as a Catalyst

Vaccine skepticism and opposition are not new — they have existed since the earliest days of vaccination. Edward Jenner, the English country doctor who administered the first smallpox vaccine in 1796, faced resistance despite the widespread acclaim for his discovery. By 1866, the first organized anti-vaccination group, the British “National Anti-Vaccination League,” had formed. Opponents feared vaccination might cause more harm than good. Caricatures depicting people growing cow heads from their arms after vaccination circulated, and early anti-vaccine publications appeared.

Since then, criticism and opposition have accompanied nearly every new vaccine introduced. The COVID-19 pandemic significantly accelerated the spread of anti-vaccine content, acting as a catalyst for alarmist and conspiratorial narratives that had previously remained largely under the public radar. With COVID-19, organized anti-vaccine movements gained unprecedented visibility and influence.

The effects have been long-lasting. In vulnerable populations, vaccine myths not only influenced decisions regarding COVID-19 vaccination but also fueled broader skepticism toward vaccines in general. Experts are now exploring ways to reverse this trend. Recent research into modifiable underlying attitudes and concerns across different populations offers promising avenues for intervention.

Modifiable Risk Factors

A mixed-methods study conducted by doctors and psychologists from the universities of Oxford and Oslo, involving comparable populations from Norway and the UK, identified five key modifiable risk factors associated with COVID-19 vaccine skepticism:

1. The illusion of invulnerability,
2. Doubts about vaccine effectiveness,
3. Distrust of (health) authorities,
4. Downplaying the societal impact of COVID-19, and
5. Health-related fears concerning the vaccine.

These risk factors have strong predictive value and can be strategically addressed by public health organizations to reduce vaccine hesitancy.

Both vaccine opposition and hesitancy stem largely from misconceptions about the actual risks, benefits, and potential side effects of vaccines and their adjuvants. Most people who remain undecided do not reject vaccines out of firm conviction. There are multiple opportunities to address uncertainties and counter misinformation with well-founded evidence.

Traditional educational approaches have proven to be as effective as newer motivational interventions aimed at increasing personal motivation to get vaccinated. Both strategies have helped raise vaccination rates. However, there is still a lack of high-quality studies evaluating the effectiveness of motivational methods in more detail.

Can Anti-Vaccine Movements Be Reversed?

Anti-vaccine activism is not confined to the general public; even some healthcare professionals are susceptible to vaccine skepticism and may inadvertently contribute to the spread of misinformation — often via the same channels as nonexperts. When such views come from medical professionals, the impact is especially damaging. The high credibility generally afforded to doctors lends greater weight to their vaccine-related statements than those from former classmates or alternative medicine practitioners.

The spread of false or biased information about vaccines amounts to an attack on science itself — a reality that many fail to recognize. Medical assessments of vaccines, adjuvants, or new vaccine technologies are sometimes deliberately downplayed or misrepresented to bolster anti-vaccine narratives. These groups use such claims to suggest contradictory scientific opinions on vaccines exist, despite a clear consensus among experts supporting vaccination.

Recent developments in the US highlight the dangers of coordinated misinformation. In June, all 17 permanent members of the Advisory Committee on Immunization Practices were dismissed and partially replaced with known vaccine critics and underqualified individuals. Experts have warned that this move severely undermines trust in the committee’s future recommendations.

It is concerning that even health authorities can fall under the influence of anti-vaccine groups, with real consequences for official vaccine policies. While such scenarios remain unthinkable in Germany and other European countries, it is crucial to proactively resist attempts at influence, counter misinformation, and communicate the scientific basis of vaccine decisions clearly and accessibly.

Doctors and healthcare professionals often lack the time to provide detailed information and persuasion to vaccine-skeptical individuals or those unsettled by misinformation. However, in many cases, extensive information isn’t necessary — simply highlighting the health benefits of vaccination and directing patients to reliable online resources can be sufficient. For example, the Robert Koch Institute, Berlin, Germany, offers alphabetically organized, easy-to-understand information from the German Standing Committee on Vaccination on each available vaccine, along with answers to frequently asked questions, under the title “ Vaccinations AZ.”

Making Vaccines More Accessible

Another often overlooked factor in vaccine hesitancy is that missed vaccinations can result from a lack of information, misunderstandings, or simply forgetting appointments. Limited language skills may hinder understanding of vaccine information, while patients might hesitate to ask questions. Multilingual brochures can help by enabling patients to review information at their own pace and raise queries at follow-up visits. In Germany, for example, the current vaccination schedule is available in 10 languages.

Physicians can also help reduce missed appointments by setting up automatic reminders via apps, email, or short message service. Since 2025, vaccination records for all insured individuals have been accessible through the digital vaccination pass, unless the individual opts out. Patients can also enroll in personalized vaccination reminder services to stay on schedule.

This story was translated from Univadis Germany.

For a few dozen people in the world, the downside of living with a rare immune condition comes with a surprising superpower—the ability to fight off all viruses.

Columbia immunologist Dusan Bogunovic discovered the individuals’ antiviral powers about 15 years ago, soon after he identified the genetic mutation that causes the condition.

At first, the condition only seemed to increase vulnerability to some bacterial infections. But as more patients were identified, its unexpected antiviral benefits became apparent. Bogunovic, a professor of pediatric immunology at Columbia University’s Vagelos College of Physicians and Surgeons, soon learned that everyone with the mutation, which causes a deficiency in an immune regulator called ISG15, has mild, but persistent systemic inflammation.

“The type of inflammation they had was antiviral, and that’s when it dawned on me that these individuals could be hiding something,” Bogunovic recalls. When he and his colleagues looked at the individuals’ immune cells, they could see encounters with all sorts of viruses—flu, measles, mumps, chickenpox. But the patients had never reported any overt signs of infection or illness.

“In the back of my mind, I kept thinking that if we could produce this type of light immune activation in other people, we could protect them from just about any virus,” Bogunovic says.

Today, Bogunovic is closing in on a therapeutic strategy that could provide that broad-spectrum protection against viruses and become an important weapon in next pandemic.

In his latest study, published Aug. 13 in Science Translational Medicine(link is external and opens in a new window), Bogunovic and his team report that an experimental therapy they’ve developed temporarily gives recipients (hamsters and mice, so far) the same antiviral superpower as people with ISG15 deficiency. When administered prophylactically into the animals’ lungs via a nasal drip, the therapy prevented viral replication of influenza and SARS-CoV-2 viruses and lessened disease severity.

In cell culture, “we have yet to find a virus that can break through the therapy’s defenses,” Bogunovic says.

Mimicking the immune superpowers of a rare condition

Bogunovic’s therapy is designed to mimic what happens in people with ISG15 deficiency, but only for a short time.

Instead of turning off ISG15 directly—which leads to the production of more than 60 proteins—Bogunovic’s therapeutic turns on production of 10 proteins that are primarily responsible for the broad antiviral protection.

The current design resembles COVID mRNA vaccines but with a twist: Ten mRNAs encoding the 10 proteins are packaged inside a lipid nanoparticle. Once the nanoparticles are absorbed by the recipient’s cells, the cells generate the ten host proteins to produce the antiviral protection.

“We only generate a small amount of these ten proteins, for a very short time, and that leads to much less inflammation than what we see in ISG15-deficient individuals,” Bogunovic says. “But that inflammation is enough to prevent antiviral diseases.”

Foundation for future therapy

Bogunovic’s team sees their technology as a weapon for the next pandemic—providing protection for first responders, people in nursing homes, and family members of infected individuals—regardless of the responsible virus.

“We believe the technology will work even if we don’t know the identity of the virus,” Bogunovic says. Importantly, the antiviral protection provided by the technology will not prevent people from developing their own immunological memory to the virus for longer-term protection.

But the technology’s drug delivery and absorption properties still need optimization. When delivered to animals via nanoparticles, the 10 proteins were produced in the lungs, “but probably not at high enough levels that makes us comfortable going into people immediately,” Bogunovic says.

“Once the therapy reaches our cells, it works, but the delivery of any nucleic acid, DNA or RNA, into the part of the body you want to protect is currently the biggest challenge in the field.” The researchers also need to determine how long the therapy’s antiviral protection will last, currently estimated at three to four days.

“Our findings reinforce the power of research driven by curiosity without preconceived notions,” Bogunovic says. “We were not looking for an antiviral when we began studying our rare patients, but the studies have inspired the potential development of a universal antiviral for everyone.”

Reference: Akalu YT, Patel RS, Taft J, et al. An mRNA-based broad-spectrum antiviral inspired by ISG15 deficiency protects against viral infections in vitro and in vivo. Sci Transl Med. 17(811):eadx5758. doi: 10.1126/scitranslmed.adx5758

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