Covid-19, flu, RSV: Here are the vaccine recommendations for fall—and the best time to get them

Virus Alert: Covid-19 Still Doing The Rounds, Peak In RSV Infections And Flu Facts

With winter approaching, here's what to know about this season's flu, respiratory infections and the lingering presence of Covid-19.

The latest update from the National Department of Health will make anyone think twice about heading to Tiffindell for a lekka jol in the snow. Apparently the respiratory syncytial virus (RSV) is already at peak circulation in South Africa, flu cases are starting to surge, there's a resurgence of swine flu and Covid-19 continues to circulate.

"The National Institute for Communicable Diseases has a surveillance system which monitors the circulation of respiratory viruses throughout the country and has notified the department that it is currently the peak season of RSV which can be confused by some people with Covid-19 or SARS-CoV-2 due to common symptoms," revealed the department's spokesperson, Foster Mohale.

Dr Jonathan Redelinghuys of Medicare24 recently told The Citizen that the resurgence of swine flu, alongside a strong showing of seasonal flu, presents a significant health risk and the potential for a severe flu season.

Latest strain of Covid-19: 'No reason for concern'

In September last year, the World Health Organization [WHO] announced that the latest Covid-19 variant which has been detected, is known as JN.1.

In January, the JN.1 variant was also confirmed in samples from South Africa.

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Dr Sibongile Walaza from the NCID told Daily Maverick that Covid-19 is still circulating in South Africa, adding that new variants are expected to continue to emerge. 

JN.1 is the latest Covid-19 strain which has emerged. Photo: iStock

"With currently available data, albeit limited, there is no reason for concern. The WHO has assessed the overall risk as low as the limited evidence on JN.1 does not suggest additional public health risks relative to the other currently circulating Omicron descendent lineages," Walaza continued. 

"Individuals at risk of severe disease [older people, immune compromised] are recommended to receive vaccine and booster doses as per guidelines."

The latest report from South African teams tracking SARS-CoV-2 viruses published on 5 January states that 11 samples of the JN.1 variant were found in the Western Cape and one in Gauteng.

Fake news about new variant circulating

Mohale said that the department has noted with concern that fake news about a Covid-19 Omicron XBB variant has resurfaced on social media.

In the post, people are advised to wear face masks because of this alleged deadly and not-easy-to-detect variant.

"This is a misleading message which first resurfaced during the peak of the pandemic without a traceable source," the spokesperson warned.

"We urge members of the public to be vigilant and ignore this malicious social media content whose intent is to cause unnecessary panic and confusion, especially as the country is entering influenza season."

ALSO READ: Covid lowered life expectancy by 1.6 years worldwide: study

There's flu and then there is RSV

Respiratory syncytial virus or RSV is the most common cause of bronchiolitis and lower respiratory tract illness (LRTI) among young children. However, it may also contribute to respiratory disease in older people. 

According to the Health Department, it is highly contagious and infection with RSV does not result in permanent or long-term immunity and re-infections can occur.

The majority of infants with RSV-associated bronchiolitis do not require hospitalisation, but certain children are at risk of severe disease or require supplemental oxygen.

Infants under six months may develop severe disease like hypoxia, severe respiratory distress (tachypnoea, nasal flaring or lower chest retractions), inability to feed or apnoea requiring hospitalisation.

Flu season approaching

The flu season is expected to start in the next few weeks and the department is advising those at high risk of contracting the virus to get the flu vaccine to prevent severe health complications. 

Groups at high risk include people who are over 65 years old, those with underlying illnesses such as heart and lung disease, people living with HIV and tuberculosis, as well as pregnant people. 

Stay ahead of the curve and get your flu vaccine. Photo: iStock

The flu vaccine is available in public clinics free of charge on a first-come, first-serve basis to people falling into the high-risk category, while private pharmacies also sell the vaccine. 

The flu virus spreads mainly from one person to another by respiratory droplets and co-infections with other respiratory viruses can occur. 

Some common symptoms of RSV and flu include – but are not limited – to a runny nose, loss of appetite, coughing, sneezing, fever, and wheezing.

People infected with the flu are usually contagious for three to eight days. Preventative measures such as wearing masks and social distancing are recommended especially for those who are ill. 

Debunking myth that influenza vaccine can give you flu

False: According to the NICD, the vaccine does not contain a live virus so you cannot "catch" flu from the vaccine.

At the time when influenza vaccine is recommended (just before the flu season), there are many other types of respiratory viruses around that can cause similar signs and symptoms to flu.

There is a high chance of being infected with one of these viruses and people often – incorrectly – attribute the illness to a flu shot they've just had.

The vaccine also takes two weeks to work so you could catch flu during this period, especially if you receive the influenza vaccine after the flu season has started.

It is also important to note that the flu vaccine needs to be repeated every year as flu viruses change slightly each year.

Moderna Says FDA Delaying Decision On RSV Vaccine Approval

Vials are filled in a photo illustration depicting mRNA technology. ()

US regulators' decision on whether to approve Moderna Inc.'s vaccine for RSV has been delayed due to "administrative constraints" at the Food and Drug Administration, as the company works to get its second product to market.

The FDA hasn't informed Moderna of any issues related to vaccine safety, efficacy or quality that would prevent approval, Moderna said Friday in a statement. The agency is now working to conclude its review of the vaccine by the end of May, the company said. A decision had been expected by May 12.

Moderna's sales have fallen drastically as the market fades for Covid shots. The company has looked to the RSV vaccine as an entry into another promising area. RSV shots from GSK Plc and Pfizer Inc. That gained US clearance last year generated about $2.4 billion in combined sales, with GSK leading the market.

The FDA didn't ask for any major changes to Moderna's license application or issue a continuing response letter, which would have indicated that it wouldn't be approved in its current form, said Michael Yee, a Jefferies analyst.

"We don't expect major delays from here onwards," he said in a note. Wall Street's fears of a "worst case scenario" should now be lifted, he said.

If Moderna's shot were approved by the end of May, the company would still be able to participate in a meeting of government vaccine advisers scheduled for late June that would be required for a recommendation for use, Myles Minter, an analyst with William Blair, said in note.

Moderna's shares fell as much as 3.8% at the US market open.

Breast Milk's Secret Weapon Against RSV Revealed In New Study

In a recent review published in the journal Advances in Nutrition, researchers examined the current evidence on the role of human milk oligosaccharides (HMOs) in protecting infants against respiratory syncytial virus (RSV) infection and disease, highlighting potential mechanisms and future research directions.

Potential role of hMOS on RSV disease. HMOS such as 2'-FL and LNnT are metabolized by Bifidobacterium in the infant's gut into short-chain fatty acids, like acetate. Small quantities of hMOS and acetate are absorbed and can reach the lungs through the circulation, where they could act as antivirals and modulate inflammation. Small quantities of hMOS and short-chain fatty acids could also coat the upper respiratory mucosa in the form of regurgitated milk, as seen in the noses of breastfed infants. Review:  Human milk oligosaccharides and respiratory syncytial virus infection in infants

Background

RSV, a common cause of pediatric respiratory infections, particularly impacts infants under two years, with significant morbidity and mortality. Beyond the immediate health impact, RSV infection could also affect long-term immune development and overall health outcomes.

The heavy disease burden of RSV infection in infants, coupled with the lack of effective treatments, highlights the urgent need for prophylaxis strategies. Breastfeeding is shown to offer consistent protection against severe RSV disease, potentially owing to the bioactive components in breast milk, including HMOs. Recent studies have associated HMOs with lower respiratory infection risk and reduced viral load and inflammation in infants, highlighting their potential role in preventing and managing RSV infection.

Overview of human milk oligosaccharides

HMOs, abundant in human milk, play diverse roles in infant development. They are synthesized from lactose and can form various structures with additional sugars like GlcNAc, Gal, Fuc, and Neu5Ac. The concentration and composition of HMOs vary among individuals and populations due to genetic and environmental factors. HMOs are resistant to digestion and reach the colon intact, where they modulate the microbiome, inhibit pathogen binding, reduce inflammation, and modulate the immune system, potentially contributing to the prevention of viral infections in breastfed infants.

HMOs reduce the risk of respiratory infections

Clinical studies have explored the association between HMOs and respiratory symptoms in infants, particularly focusing on their potential preventive effects against RSV infection and other respiratory diseases. Lower levels of lacto-N-fucopentaose II (LNFP-II) in maternal milk and infant feces were found to be associated with increased respiratory symptoms in infants. Another study demonstrated that infant formula containing 2'-fucosyllactose (2'-FL) and lacto-N-neotetraose (LNnT) reduced the incidence of lower respiratory tract infections and bronchitis in infants. Additionally, the maternal secretor genotype, which affects the production of α1-2 fucosylated HMOs, was found to be associated with a reduced risk of acute respiratory infections in breastfed infants. However, some studies did not find a significant association between HMOs and respiratory infections. Further research is needed to elucidate the precise mechanisms and effects of HMO consumption on RSV incidence and severity, considering factors such as HMO composition, secretor status, and microbiome composition.

HMOs show antiviral activity

HMOs exhibit antiviral properties by binding to clinically relevant viruses, including rotavirus, norovirus, human immunodeficiency virus (HIV), and influenza. For instance, α1-2 fucosylated HMOs like 2'-FL can occupy norovirus binding sites, reducing infectivity. Additionally, certain HMOs compete with HIV-1 for binding sites on dendritic cells, potentially reducing transmission. Despite human milk's ability to transmit viruses, it rarely causes disease in infants, likely owing to the antiviral properties of HMOs. The structural diversity of HMOs provides a wide range of protection against viral infections, with implications for preventing diseases like coronavirus disease 2019 (COVID-19). However, research on HMOs's ability to preclude RSV infection and pro-inflammatory responses remains limited compared to other viruses.

Altering the host's innate response

Exposure to certain HMOs alters the response of human respiratory and peripheral blood mononuclear cells (PBMCs) to RSV infection. These HMOs are shown to reduce RSV viral load and cytokines linked to disease severity and inflammation in respiratory cells and PBMCs. Infants fed formula containing 2'-FL also exhibit lower plasma levels of inflammatory cytokines when challenged with RSV, similar to breastfed infants. Thus, HMO supplementation may enhance resistance to RSV infection in infants, potentially explaining the reduced risk of severe RSV disease observed in breastfed infants.

Modulation of gut microbiome to mitigate RSV disease severity

The gut-lung axis concept suggests that gut microbiota can influence immune defense against respiratory infections like RSV beyond the gastrointestinal tract. Changes in the gut microbiome and the associated metabolites are found to be linked to the incidence and severity of respiratory infections such as RSV.

Research on infant formula indicates that 2'-FL and LNnT can promote a Bifidobacterium-dominated microbiota in some infants, potentially reducing the need for antibiotics. Additionally, elevated fecal fucosylated glycans, lactate, acetate, and Bifidobacterium are associated with reduced risk of bronchitis or lower respiratory tract infections in infants.

Acetate, produced by gut bacteria in response to specific HMOs, may enhance immune responses against RSV infection. Animal studies demonstrate that acetate supplementation can protect against RSV-induced lung inflammation, and clinical observations in infants with RSV bronchiolitis suggest that high levels of fecal acetate are associated with milder symptoms.

Conclusion and future perspectives

HMOs show promise in combating RSV through multiple mechanisms, including direct antiviral action and gut microbiota modulation. Standardized methods for identifying HMOs are essential. Future studies should optimize designs to investigate HMOs effects on RSV. Extensive birth-cohort studies could provide valuable insights. Key questions include identifying specific HMOs protective against RSV and understanding their mechanisms of action.

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