Diseases and Conditions: Diseases Symptoms, Treatment, Signs ...

What Is A Pneumococcal Infection? Hong Kong NGO Says Half Of At-risk Residents Don't Know, With Experts Calling For More Free Jabs

Half of Hongkongers at risk of contracting pneumococcal infections are clueless about the disease, a survey has found, with experts urging authorities to expand a free jab scheme combating the bacteria linked to the city's second-deadliest medical condition.

The study published by the Hong Kong Alliance of Patients' Organisations and Polytechnic University's nursing school on Sunday also discovered that three-fifths of respondents had yet to receive any pneumococcal vaccination.

The poll was conducted between June and August this year to learn more about residents' understanding of the bacteria and where to get vaccinated, with the survey covering 2,014 people aged 50 and above.

Nearly 80 per cent of adult Hongkongers not vaccinated against pneumococcus: survey

Pneumococcus, a bacteria found in the upper respiratory system, is one of the most common causes of pneumonia, which was ranked as the second deadliest in Hong Kong after cancer and linked to 10,499 deaths last year.

"With pandemic prevention measures relaxing, we're seeing a resurgence of serious illnesses linked to pneumococcal infections back to pre-Covid levels," said Hong Kong Geriatrics Society president Stanley Tam Kui-fu.

The Centre for Health Protection recorded 37 cases of pneumococcal infections in Hong Kong between May and July of this year. In comparison, the city logged 29 cases over the same period in 2019.

"The elderly, particularly those grappling with chronic diseases, are at a significant risk. Their likelihood of hospitalisation due to pneumococcal pneumonia is more than 10 times higher than those aged 18 to 49," Tam said.

University of Hong Kong Professor Ivan Hung has urged authorities to expand the city's pneumococcal vaccine programme. Photo: Xiaomei Chen

Government figures showed only about 42 per cent of residents aged 65 and above had received a pneumococcal vaccination during the 2022-23 season.

The survey found that half of the 2,014 people interviewed were at high risk of contracting a pneumococcal infection. A further breakdown showed a quarter were diabetic, 16 per cent had long-term cardiovascular diseases and 9 per cent were obese.

Half of all interviewees admitted to not knowing about vaccination options, while 50 per cent said they were unaware of any government subsidies on offer or the city's free jab scheme for those aged 65 and above.

70% of Hongkongers at risk of chronic kidney disease refuse treatment: doctors

Under the initiative, potential recipients must be considered as being at high risk of infection, and staying at a public hospital or living in a care home for the elderly or disabled.

Polytechnic University nursing professor Angela Leung Yee-man, who led the research effort, said: "The survey results show that, in addition to strengthening disease education, information about vaccines needs to be more targeted and easier to understand to increase the vaccination rate among the elderly."

Local authorities currently offer two types of pneumococcal vaccines that inoculate patients against either 13 or 23 antigen strains, which are also available at private clinics for HK$800 (US$102) and HK$400, respectively.

Healthcare specialists cool to expanded Hong Kong elderly voucher scheme

Two new jabs that protect against 15 and 20 antigen strains were registered for use with the Department of Health in 2022 and earlier this year, respectively.

Professor Ivan Hung Fan-ngai, the chair professor of infectious diseases at the University of Hong Kong, suggested authorities update their vaccination recommendations to include new shots and expand the funding for the current scheme to offer greater protection for those deemed to be at high risk.

Hong Kong Alliance of Patients' Organisations president Yuen Siu-lam said the government should also consider offering free vaccines to all people aged 65 and above, as well as subsidising jabs for those between 50 and 64.

Influenza, Bronchiolitis, COVID-19, Pneumococcal Infections: Preventing Respiratory Infections As Winter Approaches

As the winter season approaches, the Ministry of Health would like to remind the public of the importance of protecting themselves against the most common respiratory infections in Luxembourg, such as influenza, RSV bronchiolitis, other viruses responsible for respiratory tract infections and COVID-19. They are all contagious and can cause epidemic waves. There can also be superinfections caused by bacteria such as pneumococcus, the most common cause of bacterial pneumonia in Europe. In winter, these infections can affect a large proportion of the population, leading to saturation of the medical and hospital systems.

According to figures from the Kannerklinik at the Centre hospitalier de Luxembourg (CHL), between November and December 2022, 263 children under the age of 2 had to be admitted to hospital with bronchiolitis. In addition, during the 2022-2023 winter season (which runs from October 2022 to May 2023), 53,646 cases of COVID-19 and 10,709 cases of influenza were recorded.

In this context, the Ministry of Health is organising an awareness-raising campaign (posters, radio adverts, social networks, etc.) to prevent the spread of these viruses, by informing people about the precautions to take and the vaccinations currently available to protect against respiratory infections.

Preventive measures against respiratory infections: vaccination and hygiene measures

The viruses responsible for bronchiolitis, influenza and COVID-19 are easily transmitted from person to person by droplets (caused by coughing or sneezing) or by direct contact with hands or an object contaminated by the secretions of an infected person. Confined, poorly-ventilated and crowded places are particularly conducive to the transmission of these diseases.

Vaccination is an effective way of protecting against respiratory infections and the serious complications they can cause. People at risk are encouraged to get vaccinated against influenza and COVID-19. It's recommended to consult your general practitioner for advice on whether vaccination against these infections is advisable. In addition, vaccination against pneumococcus (which can complicate certain viral infections) can reduce serious superinfections such as pneumonia in children under 5 and people aged 65 and over.

A new treatment, administered by intramuscular injection to prevent infections caused by the bronchiolitis virus, has arrived in Luxembourg. Starting with the 2023-2024 winter season, it can be offered to newborns as soon as they are born in the maternity ward.

A number of barrier measures are also recommended to limit the transmission of these diseases, including regular hand-washing, airing out indoor spaces, limiting close contact or wearing a mask, particularly with people who are ill, and avoiding crowds and gatherings during the winter season.

Compliance with these preventive measures will help to limit the spread of viruses and relieve the pressure on healthcare systems, which are under heavy strain during the winter months.

For further information on preventive measures and vaccination against respiratory infections, consult the "Grippe saisonnière", "Bronchiolite", "Coronavirus" and "Infections à pneumocoques" sections in the "Espace Citoyen" of the sante.Lu website.

New recommendations from the Higher Council for Infectious Diseases (Conseil supérieur des maladies infectieuses, CSMI) regarding vaccination against COVID-19 and the new immunisation against the bronchiolitis virus have been published and are available on sante.Lu.

What are these infections and what are the symptoms?

Seasonal flu is an infectious and highly contagious viral disease that occurs every year. The most common symptoms of flu are a sudden onset of fever, chills, headache, muscle aches and a cough. Symptoms generally disappear after a maximum of 7 days.

Flu can cause complications, either directly or because it encourages superinfection by bacteria such as pneumococcus. Otitis, sinusitis, pneumonia, meningitis and, more rarely, encephalitis may occur. Complications occur more frequently in young children and the elderly, as well as in people suffering from other chronic illnesses that predispose them to infections, particularly respiratory infections.

COVID-19 is a disease caused by the SARS-CoV-2 virus. Symptoms range from mild to severe, with varying degrees of involvement of the respiratory tract. It is accompanied by fever, cough, breathing difficulties and fatigue. Loss of sense of smell and/or taste, digestive symptoms and skin rashes are other symptoms of the disease. The elderly, pregnant women and people with certain pre-existing chronic conditions are more vulnerable and exposed to the risk of complications.

RSV bronchiolitis is a very common respiratory infection in infants under the age of two. It appears mainly during the winter months. It is caused by a virus called respiratory syncytial virus (RSV), which causes inflammation of the respiratory tract: nose, throat and bronchi. In infants, the bronchial tubes are small and are more easily blocked by secretions, requiring the child to make sometimes considerable efforts to breathe. A baby who has difficulty breathing can quickly become tired because his muscle reserves are insufficient.

The Streptococcus pneumoniae or pneumococcus bacteria can cause relatively mild infections such as ear infections and sinusitis, more serious infections such as pneumonia and invasive infections such as meningitis.

Pneumococcus is part of the microbial flora of the throat and nose of many people (30-60% depending on age). However, it can sometimes cause infection, especially in the case of viral infections such as influenza, which damage the cells in the respiratory tract and allow the pneumococcus to become more virulent. These infections can be fatal or leave serious after-effects.

The conjugate vaccines offered to children and adults aged 65 and over provide protection against infections caused by the most aggressive pneumococci, which are the main cause of serious forms of infection.

If you have any questions about vaccination or if you have any doubts about your symptoms, you should consult your general practitioner.

Press release by the Ministry of Health

Respiratory Syncytial Virus Co-infections Might Conspire To Worsen Disease

The respiratory tract is a rich ecological niche. In addition to the regular residents of the virome and microbiome, infectious agents such as influenza and respiratory syncytial virus (RSV) come and go, and sometimes overlap. RSV can cause acute illness and the virus can sometimes linger. Viruses that stick around can cause chronic conditions such as asthma1, and could potentially change the course of future respiratory infections.

Today, polymerase chain reaction (PCR) diagnostics that can detect multiple pathogens are commonplace. Clinicians can swab a child's nose, then send the sample to a hospital laboratory to test for 20 or more pathogens including SARS-CoV-2 and other coronaviruses, rhinovirus, various strains of influenza and RSV. Armed with multiplex PCR, which is able to detect multiple pathogens at once, clinicians now know that respiratory pathogens almost never appear alone.

Part of Nature Outlook: Respiratory syncytial virus

These multiplex diagnostic tests only came into broader use around 2015, says Carolina López, a molecular microbiologist who studies RSV and other respiratory viruses at the Washington University School of Medicine in St. Louis, Missouri. Because the diagnostic technology is relatively new, she says, co-infections have been understudied.

So far, most studies have focused on one virus at a time, says Pablo Murcia, a virologist at the University of Glasgow, UK. Now, scientists are learning more about how RSV can change the course of other respiratory infections and vice versa. And they're trying to uncover the mechanisms behind these intricate interactions. Understanding these complex dynamics could help physicians to better predict an individual's risk of infection and the adverse outcomes from viral infections. It will also help epidemiologists to forecast population-scale infection dynamics more precisely.

Virologists are beginning to ask questions about which pathogens tend to infect cells at the same time, and whether these affect clinical outcomes. "What co-infections are more common or more impactful in the clinic?" says López. Clinical samples give infectious-disease specialists clues about what kinds of co-infection might be significant.

Perfect pairing

The strongest evidence for the potency of RSV co-infections is in bacterial pneumonia caused by Streptococcus pneumoniae, also called pneumococcus. Many children have pneumococcus bacteria in their noses, but it doesn't move into the lungs and make them unwell until provoked. But by what?

For a long time scientists have observed a correlation between RSV and pneumococcal-related diseases. Researchers suggested that RSV and pneumococcus can somehow make each other more virulent, on the basis of a few key pieces of evidence. RSV-related hospitalization rates decrease when children are vaccinated against the bacteria2, for example. And the amount of nasal pneumococcus that children can carry increases during RSV infections. But establishing a causal relationship between the two was challenging — until the COVID-19 pandemic.

A group of researchers led by Ron Dagan at the Ben Gurion University of the Negev in Beersheba, Israel, had been studying a cohort of children under the age of five since 2016, taking note when participants developed pneumococcal pneumonia and other respiratory infections2. In 2020, with social distancing measures in place, pneumococcal disease in his study "almost disappeared", says Dagan, who specializes in paediatric respiratory diseases. So did respiratory viruses, including RSV. Yet, the number of children carrying the bacteria in their noses remained unchanged, but it didn't make them sick. When social distancing was lifted, children became infected with RSV and then the bacteria did make them ill. This was evidenced when social-distancing measures were eased and viral respiratory infections roared back with a vengeance — as did pneumonia.

"There is a causative relationship between the two," Dagan says. "These viruses are very strongly influencing the pneumococcus to become virulent." RSV was the biggest contributor, causing 49% of pneumonia cases in the study.

Viral frenemies

For co-infections between RSV and other viruses, the clinical significance is murkier. In children, RSV "can cause severe infections no matter what", says Tobias Tenenbaum, a paediatrician at Sana Hospital Lichtenberg in Berlin, who specializes in infectious diseases. Viral co-infections, however, don't necessarily cause extra symptoms. Tenenbaum led a 2010 study3 that analysed a group of children for two years and found that the total amount of RSV a child had in their nose correlated with disease severity, but that co-infections with other viruses did not.

But these were early findings, and certainly not definitive. In fact, some studies directly contradict them, says Murcia. Other research has shown that when a viral infection occurs in the presence of RSV, disease severity is attenuated. The populations that were analysed differ between these studies, as do the mix of viruses and measures of severity, which might help to explain some of the discrepancies.

Tobias Tenenbaum, a paediatrician at Sana Hospital Lichtenberg in Berlin, checks on a newborn who has community-acquired pneumonia.Credit: André Puchta

Murcia hopes in vitro and animal studies, the natural next step, will provide clarity. "Most studies of co-infection are based on clinical cases, and there is a lot of variability there," says Murcia.

RSV and influenza A are a particularly vexing pair. Influenza A is one of two flu viruses that cause seasonal illness, capable of causing new influenza epidemics. Some research suggests that RSV and influenza A can exclude each other. On the basis of in vitro studies, researchers think that this might be because an immune response to one virus can trigger the release of signalling proteins called interferons that prevent the establishment of the second virus.

However, this simple, elegant explanation might not be playing out in the human population. A nine-year statistical study of 44,230 clinical cases of respiratory illness did not find any evidence of the viruses acting against each other between RSV and influenza4. The most recent flu season in Europe provides a good test case: during the winter of 2022–23 in Europe, says Tenenbaum, waves of RSV and influenza A closely overlapped. He's currently studying whether co-infection with these two viruses caused more severe disease during that season.

Murcia says that in his study4, which corrected for the seasonality of viruses to uncover other connections, "the patterns of co-infections didn't look random". The study showed that influenza viruses and non-influenza viruses negatively affected each other on a population level. Murcia decided to take an in depth look at RSV and influenza in a lab study5, expecting to see a negative association.

But his team found the opposite. They infected human lung cells with influenza A and RSV. "What caught our eyes is that they didn't seem to block each other," he says. In fact, the two viruses seem to have combined forces, fusing to form what Murcia calls hybrid viral particles, which contain both genomes. What's more, these hybrid particles can infect cells that lack surface receptors that are usually a baseline requirement for influenza infections.

"What we want to know now is whether this happens in real life," he says. Murcia is the first to pose caveats and questions about the hybrid viral particles. His lab used research strains of the viruses; will hybrids form between viruses that are isolated from people? Does this happen with other viruses? Murcia notes that both RSV and influenza A are both enveloped in a lipid coat, which might enable them to fuse together.

"There's been this debate in the field about whether you can package more than one viral genome in the same particle, even of the same virus," says López. "I think a lot of people were impressed with the work, some people believe it, some people don't, but now we have pictures," she says. Murcia's study included high-resolution microscopy images confirming the existence of the viral particles.

Making models

Virologists are now trying to work out how to move forwards out of the tangle of conflicting evidence about co-infections. Because controlled studies are hard to do in the clinic, researchers are pinning their hopes on better in vitro and animal models of co-infection. But many questions remain about how best to develop these models.

A researcher interested in mimicking co-infections in an animal or in vitro model faces a huge list of decisions, says López. First: choosing the right virus. "Are we really using the right viruses in animal models?" López wonders. "A human virus in a mouse may interact completely differently" than it does in its natural host, she says.

Molecular microbiologist Catherine Satzke and research fellow Sam Manna at the Murdoch Children's Research Institute in Melbourne, Australia, decided to use the mouse equivalent of RSV for their work on RSV–pneumococcus co-infections6. Many mouse models have used human RSV, but the virus needs be given in unrealistically high doses and doesn't replicate well in mice, says Manna. So the researchers used murine pneumonia virus (PVM), the rodent equivalent of RSV. Moreover, the team chose to work with infant mice, because RSV and its co-infections have the greatest affect on young children. Their research, published in 2022, found that the pneumococcal bacterial strain matters, too. Perhaps because some strains are already more virulent than others, and some benefit more from the presence of PVM.

López says that the unknown timing of viral co-infections makes them particularly difficult to study. Is it better to start by infecting cells with RSV, or should influenza come first? Another key set of questions relates to the length of time of infections. How long should the first virus be allowed to establish itself before the second is added?

More from Nature Outlooks

"We have a lot of viruses persisting for longer than we think," López says. But most models that are now in use focus on acute viral respiratory infections. That might not match the clinical reality. "Viruses that seem acute could persist at low levels and change the environment for the next virus," she says. "They do not function as a single entity, they are a community."

As well as timing, there are questions of location. Scientists don't know whether viruses need to infect not only the same part of the body but also the same types of cell to cause co-infections. Infecting the same cells is necessary to form the kind of hybrid particles Murcia saw in the lab, but it might not be needed to cause synergistic co-infections. López is developing an RSV co-infection model based on organoids — miniaturized versions of human tissues — that include multiple cell types from the human respiratory system. She hopes studying multiple viruses in these mixed groups of cells will help to answer some of these questions.

This research also raises queries about microbial and viral evolution. Viruses that infect the same part of the body at the same time — or prevent other viruses from infecting cells at the same time as or after them — are at the very least exerting evolutionary pressures on each other. RSV and influenza are, from a human point of view, a bad influence on pneumococcus. So, are these pathogens cooperating or is all this a coincidence? "It's hard to differentiate what's an evolutionary advantage and what's happenstance," says Satzke.

"We don't have a lot of understanding of any of this," says López. "This is the fun of science, right?"

---