'But it is only now being detected more via a test that costs about Rs 15,000 to Rs 20,000.'
'The HMPV virus typically causes mild respiratory symptoms in most people, but can be more severe in young children, the elderly, and those with compromised immunity.'
The sudden detection of new cases of human metapneumovirus or HMPV is not a matter of alarm, nor does it make news, says Dr Lancelot M Pinto, a senior respiratory disease specialist attached to the P D Hinduja Hospital and Research Centre, Mumbai.
The detection is new, not the cases or the virus.
Dr Pinto explains that human metapneumovirus or HMPV is not a new virus. It has been circulating for decades, but it is only now being detected more via a test that costs about Rs 15,000 to Rs 20,000.
"We have something called a multiplex PCR platform nowadays, which is a test that detects close to 15 viruses and bacteria on a throat swab. Now that we've started doing this more frequently, we've been identifying viruses that we didn't before.
"But since the test is so expensive, it is usually reserved for identifying what someone vulnerable and hospitalised is suffering from, to put them on a better and more accurate course of treatment.
"It would be done only in the setting of somebody who's hospitalised and you're really trying hard to figure out what the organism is, because you want to try and direct your therapy towards the right organism.
"In this PCR, for example, you can pick up COVID and influenza, two viruses for which we have a definitive treatment available.
"You also pick up bacteria and then you know that you need this specific kind of an antibiotic which helps.
"We tend to do this only for hospitalised patients because we know it's expensive. For hospitalised patients you don't want to try what we call empiric therapy (based on educated guesses). You don't have that window of waiting and experimenting, so to speak."
Otherwise, the usual round of viruses that were brought into clinics and OPDs, across India, by able-bodied, otherwise healthy people were not identified specifically but labelled, only generally, as a cold or a respiratory infection. And the PCR test was not done at "ground level" so there aren't any numbers for HMPV's frequency among healthy people.
Adds Dr Pinto, "Human metapneumovirus is one of the viruses, for example, detected on this multiplex PCR kit. We actually saw a relative surge about three months ago. We looked at our data at our hospital and in that period, there was a surge in human metapneumovirus. And I remember discussing this with my colleagues, saying that this is what the PCRs are picking up, but there's nothing much to be done about it."
What Are The Symptoms Of An HMPV Infection?
The HMPV virus typically causes mild respiratory symptoms in most people, but can be more severe in young children, the elderly, and those with compromised immunity.
So, in a nutshell, basically human metapneumovirus was I think reported (identified) somewhere around 2001, for the first time. They believe that it's been circulating around for probably half a century, even prior to that.
It causes periodic outbreaks of viral respiratory symptoms, usually in the winter and in spring is what's being described. But maybe there are other patterns as well.
"It typically causes a mild illness for most individuals -- it's a little bit of nasal congestion, a little bit of a sore throat. Some people get a cough, fever, which is very often self-limiting and last for a few days and then people get better without any specific treatment.
"But children under five, when they get infected for the first time, potentially could have more severe disease. People who are elderly and have comorbidities and waning immunity, or people who have respiratory illness such as asthma, COPD -- these are the groups in which more severe disease has been described."
This is the same cohort of people that are being identified in hospitals with metapneumovirus, says Dr Pinto and their lower immunity lands them in a hospital.
When Is A Viral Outbreak Worrying?
Dr Pinto very concisely explains further that there are three main reasons to be concerned about a virus outbreak:
1. It's a novel or new or mutated strain of an already identified virus;
2. There's atypical severity affecting populations, where such severity has not been seen before;
3. There is extremely high transmissibility.
"Broadly, these would be the reasons to be concerned about any virus. None of these seem to be the case for this outbreak in China right now. As of now, they've not reported anything atypical yet."
An example of an atypical situation, Dr Pinto explains is like when in 2009, swine flu or H1N1 had a lot of pregnant women and young people getting affected and landing up in the ICU. -- "That was a sudden cause for concern that there was a strain of flu which was affecting young people and pregnant women."
Another sample of atypical behaviour is higher transmission. "If the novel mutation renders the virus more transmissible, then you might see, for example, a whole classroom falling sick together or a whole workplace falling sick together."
Detection Of HMPV Cases Is Not News
The physician points out that the news headlines indicated something new was going on in connection with this virus, when it wasn't. "The moment this got announced, we have people saying, first case detected in a particular state, or we've had a baby test positive for this virus. I mean, babies have been testing positive for this virus for a long time. And we know that cases exist.
"Where is the question of saying this is the first case in a state or we are on high alert because we've just detected it. It's just a reflection of the fact that you're probably testing more aggressively now."
Less Fear Mongering
The physician advocates for a far more balanced approach -- neither trivialising nor sensationalising potential outbreaks -- but asking the right questions to determine if there is cause for concern, which in this case there has not been so far.
"Theoretically if this HMPV was a novel strain, then it would follow the pattern which we saw with COVID-19. So changed behaviour is exactly what happened for Covid, right? We had SARS-CoV-1 already existing. We knew there was a SARS epidemic, which began in 2002. But what happened in 2019, 2020 was a novel strain of the earlier virus."
If, for example this was a novel strain of HMPV, the story of the new HMPV virus would unfold like the story of COVID-19.
"There would be reports of increasing hospitalisations, that would lead to whole genome sequencing, looking at what exactly is novel about the virus. You would then be on high alert and isolate people who are ill. It pretty much would follow the trajectory what we went through with COVID-19."
When cases of HMPV were being identified recently, the right questions had to be asked. "Is it a new strain? Are atypical patients, who traditionally do not get infected with it, getting infected? Is there a surge in hospitalisation, especially among individuals who ordinarily wouldn't get hospitalised with this virus? Once you have that information you can make an informed statement about whether this is of concern or not of concern."
According to Dr Pinto both ends of the spectrum are dangerous. "Being in a hyper-alert, hyper-vigilant state is not good for anyone. But at the same time being lax also is not good for anyone either. So, for example, if you get news that there is an outbreak in China, to instantly say 'Oh, we've been seeing human metapneumovirus forever, so therefore it's nothing to be concerned about' and shrugging your shoulders, that would be letting your guard down."
IMAGE: Dr Lancelot M Pinto.
Photograph: Kind courtesy Dr Lancelot M Pinto
Surveillance Should Pick Up A Virus First
Dr Pinto also feels that the manner in which news of virus detection or potential outbreaks gets out does not follow a correct pattern. "This direction of information seems to be going in the wrong way. It's like the clinicians discovering it. Then somebody speaks to the media, then the media talks about it. Then the government issues an advisory at some point saying, 'Oh, it's not so bad. Don't worry. We are watching the situation'.
"Whereas in an ideal world, the surveillance needs to pick it up first, inform the clinicians that this is what we are seeing, so if you want to start treatment without evidence on day one, this is the drug that you need to give etc."
Dr Pinto makes a case for better real-time surveillance and public information systems, such as a dashboard showing current infection trends, to help allay fears and provide accurate information quickly.
"Why can't we have a transparent dashboard on which everything's kind of there and (tells you) this is what we're picking up right now. You look at your locality, look at the city of Mumbai... For example, the multiplex PCR testing information is with the companies; there are one or two companies which mainly provide the service. They should be mandated to notify (authorities).
"It is not rocket science to have a dashboard on which you know, real time, that for example right now it's only influenza and Covid. It's not that challenging to create a dashboard in which I could just look at today's date and by the end of the day you would know what were the major infections picked up in the city of Mumbai, for example."
Feature Presentation: Rajesh Alva/Rediff.com
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