New Scientist - 02.18.2020

54 | New Scientist | 8 February 2020

Going viral

I had my flu vaccination, then

promptly came down with a really

bad case of flu three weeks later.

How can that happen?

Nikki Walters,

Wakefield, West Yorkshire, UK

The first possibility is that perhaps

it wasn’t the flu. The vaccine only

protects against the influenza

virus but there is a whole menu

of possibilities when it comes to

diseases with flu-like symptoms.

Secondly, even if it was

influenza that you had, there is a

chance you caught a strain that

wasn’t covered by the vaccine.

There are many different strains

of influenza virus, and several

can be circulating at once.

Jane Monroe

Arcata, California, US

Every year, immunologists must

predict which strain, or strains,

of flu virus will dominate during

flu season. This is so the correct

vaccine can be produced. Making

this prediction is difficult, so

sometimes the vaccine doesn’t

match the virus strain that

is circulating most widely.

There are multiple strains of

influenza virus circulating during

flu season, and you may have

been infected by one of those that

wasn’t included in the vaccine.

Lewis O’Shaughnessy

London, UK

More than 200 different viruses

cause flu-like symptoms. Each has

different antigens – parts of the

virus that would be targeted by

antibodies – and so requires a

different vaccine. On top of this,

influenza viruses are able to

mutate rapidly, so vaccines are

only effective for a few years.

Rob Colebrook

Clee Hill, Shropshire, UK

Firstly, and most importantly, a flu

vaccine can’t give you influenza.

Secondly, unless you had a blood

test or nasal swab to prove it, it

is unlikely that you actually had

influenza. When I practised as a

GP, the vast majority of patients

who thought they had influenza

were more likely to have been

infected with a parainfluenza

virus – which is like influenza –

or a rhinovirus or adenovirus,

which both cause a cold.

Thirdly, it takes between two

and four weeks after having the

vaccine for antibodies to influenza

to develop, so it is possible to get

flu before you have full protection.

Michael Allen

Ottawa, Ontario, Canada

A surveillance system developed

by the World Health Organization

attempts to identify the strains of

flu circulating around the world

from swabs of the nose and throat

of patients with flu symptoms.

The WHO then recommends

the strains to be included in the

vaccine for the upcoming season.

There isn’t always a good match

between the strains in the vaccine

and those that actually cause

influenza that year. In addition,

some countries, including

Australia, choose to follow

their own recommendations

rather than those of the WHO.

A 2018 review by the Cochrane

Collaboration found that flu

vaccine cuts the risk of healthy

adults getting influenza from

2.3 per cent without vaccination

to 0.9 per cent with it.

John Philpott-Howard

London, UK

Vaccines are never 100 per cent

effective in all people, although

two doses of measles vaccine (as

MMR) come close, giving more

than 99 per cent protection.

Also, immunisation can result

in a suboptimal immune response,

for a variety of reasons: poor

vaccine administration technique,

for example, or because of other

health problems affecting your

immune system at the time.

It is important to note that even

if you get infected by the influenza

strain that is in the vaccine that

year, it is likely that you will have a

modified illness. Although it may

feel like a bad case, the vaccine

may have partially protected you

from even more severe disease.

Tim Lewis

Consultant chest physician,

Landshipping, Pembrokeshire, UK

It is possible to be infected with

influenza virus when attending a

crowded surgery for the injection

and fall ill before immunity has

had time to develop.

Anna Butcher

Brookton, Western Australia

My GP advises vaccination

some months ahead of the flu

season so that I have maximum

immunity when it arrives.

David Critchard

Exeter, Devon, UK

Like me, my son is allergic to

vaccines cultured in eggs.

I decline to be vaccinated, but

he is a surgeon, so is vaccinated

as soon as the latest one

becomes available. He is

then ill, sometimes needing

intensive therapy unit treatment

for up to a month.

Two years ago, he was

vaccinated and had the allergic

reaction. Some time afterwards,

a patient was flown in, having

been shot in a remote region of

Pakistan, where people often go

unvaccinated. He was patched

up, but my son and his colleagues

went down with a dangerous flu.

It hadn’t been included in that

year’s vaccine. My son infected

his sister. The virus killed the

baby she was carrying and

almost killed her.

Even if the effects of

vaccination can be unpleasant,

the consequences from the lack

of it can be much worse. ❚

This week’s new questions

Awful eaters Foxes have the most repulsive smell, alive

or dead. We often see dead foxes on our farm and they just

decompose in situ. So, does anything eat foxes? Anna Butcher,

Brookton, Western Australia

The nose knows Rust doesn’t appear to release molecules

into the air? So how does it have a smell? Hugh Cartwright,

Victoria, British Columbia, Canada

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The back pages Almost the last word

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Apart from microorganisms,

does anything eat foxes?