Chandrakant Lahariya | Flu-like illnesses' outbreak in China no real cause for concern in India

The surge in respiratory illnesses in China is once again in the news. Since mid-October 2023, there had been an increase in influenza-like illnesses -- compared to the same period in the previous three years. In mid-November 2023, the Chinese government had officially reported an increase in cases of respiratory illnesses, mainly in children but also in some other high-risk age groups. These respiratory illness cases have been attributed to seasonal influenza viruses, mycoplasma pneumoniae- a type of bacteria; respiratory syncytial virus (RSV), and also to SARS-CoV-2 (the virus that causes Covid-19).

On November 22, WHO had taken note of the situation and as part of international Health regulation, requested additional epidemiologic and clinical information, as well as laboratory results from these reported clusters from Chinese authorities. This is when it received global attention. The Indian government also held a meeting on November 26, 2023 to conduct risk assessment and analyse the preparation for any future eventuality. This was a routine and standard process and not a reason to worry or be concerned.

The reports from China have indicated the current surge has been built up on an increase in outpatient consultations and hospital admissions of children due to Mycoplasma pneumoniae since May 2023. The cases of RSV, adenovirus and influenza virus have spiked since October 2023. Officials in China have reported that no unusual or novel pathogens have been detected. Though there has been a general increase in respiratory illnesses, no unusual clinical presentation has been reported.

The experts believe that this surge is also due to the arrival of the winter season, when an increasing trend in respiratory illnesses is expected. Then, the co-circulation of respiratory viruses makes children and adults with comorbidities prone for clinical disease. Two pathogens which are being reported -- Mycoplasma pneumonia and RSV -- are known to affect children more than adults, which explains why there are more cases in children. 

The respiratory illnesses have been a reality since antiquity but Covid-19 has brought renewed attention. In fact, since the end of the Covid-19 pandemic and after the lifting of the related restrictions, the rise in viral illnesses and change in seasonality has been seen in many countries across the world. The flu season has changed in many countries and RSV related infections are more commonly being reported.

As of now, there is no reason to worry for India or any other country either. Even before the current surge of respiratory illnesses in China, in much of 2023, there have been many children and adults in India who have reported episodes of flu-like illnesses, in which the symptoms had lasted longer than usual.

A broader and scientific explanation for this phenomenon is the concept of “immunity debt”. In the last three to four years -- due to the Covid-19 related restrictions -- the circulation of common and locally circulating viruses was restricted and populations were not exposed to those viruses. As people were not exposed, they had not developed immunity against all those viruses. Then, when all restrictions are removed and mobility increased, people are being exposed to multiple viruses in one go and are getting infections. Once a major share of people get exposed to those pathogens, the transmissions would slow down.

In the time ahead, this situation may start a discussion around whether people should get another shot of the Covid-19 vaccines. The short answer is no. With current knowledge, there is no scientific rationale in getting another Covid-19 vaccine shot for any age group. The current surge is being caused by other pathogens -- different viruses and bacteria than the SARS CoV2.Then, current scientific evidence supports that two shots of the Covid-19 vaccine in settings with high natural infections continue to provide protection from severe Covid-19. There is no need for another Covid-19 vaccine shot in the foreseeable future. 

Respiratory viruses have always been around us, and our body mostly fights them off without our even knowing. However, environmental factors such as air pollution burden our immune system, which makes our body more prone to respiratory infections. Then, there is a major change in seasonality of respiratory viruses across the world, including in India.

Therefore, it is always worthwhile to protect from all respiratory viruses. Irrespective of which respiratory illness or virus is involved, general preventive measures should be followed in these settings, where increase in such illnesses is reported. The preventive measures include getting age-appropriate recommended vaccinations; staying home when ill; keeping a distance from people who are ill; getting tested and medical care as needed; ensuring good ventilation in all homes and workplaces. Winter is a common time for respiratory illnesses and more attention should be paid during that period. Eating healthy, sleeping for at least six to eight hours in a day, regular physical activity and getting treatment for pre-existing illnesses are the right approaches.

Taking a leaf from the pandemic period -- with such respiratory illnesses, there is a real challenge of misinformation. Therefore, we as a society must be more careful and avoid passing on any unverified information. We should not forward any unverified information received on the social media. The government should provide regular, timely and reliable information.

In short, the current surge of respiratory infections in a few cities of China appears to be a seasonal trend and a localised phenomenon. Considering there is no novel virus involved, it is unlikely to be a risk for other countries. It is a good time for staying informed, staying protected.