Dr Zoë Hyde Profile picture
Epidemiologist & biostatistician. @RealOzSAGE scientific advisory group member. Let's end COVID-19 with a #VaccinesPlus ventilation strategy. Opinions my own.
NotOralHistory, but actually *yes we are* Profile picture Peter English #FBPE Profile picture Jediphone Profile picture Aviva Gabriel Profile picture giovanni dall'olio 🇮🇹🇪🇺🇺🇦 Profile picture 35 added to My Authors
Jun 12 8 tweets 2 min read
A study of the hepatitis cases seen in Israel reveals they were likely a delayed consequence of COVID-19.

The average delay was 74 days (range 21-130). This is almost certainly why we’ve mostly seen negative COVID-19 PCR tests in affected kids.

No adenovirus found in liver.🧵 The authors describe 5 children with hepatitis.

Four children previously had mild COVID-19, for which they tested positive by PCR at that time.

One child had a positive antibody test for SARS-CoV-2 during the hepatitis investigation, indicating previous asymptomatic COVID-19.
Apr 21 4 tweets 2 min read
@dtjohnso: I couldn’t reply for some reason so I’m writing this. You’re sort of on the right track, except new variants essentially mean immunity (to infection) is probably short-lived for many. (Immunity to severe disease thankfully is holding up better).
This means that all bets are off when it comes to herd immunity, and a good chunk of the population will probably always be vulnerable at any given moment (unless we can develop better vaccines). But we can still try to keep transmission low with better ventilation and the like.
Mar 27 5 tweets 3 min read
Groundbreaking new research shows a far-UVC (ultraviolet light) air purification system can reduce levels of an airborne pathogen by 98% within minutes.

This is equivalent to an incredible 184 air changes per hour - better than even HEPA air cleaners.
nature.com/articles/s4159… Researchers continually released aerosolised Staphylococcus aureus bacteria into a room ventilated with 3 air changes per hour.

This bacteria is harder to kill with UV light than either influenza or the coronaviruses that cause the common cold, making it a tough challenge.
Mar 13 6 tweets 2 min read
I did an interview the other day in which I was asked when WA’s omicron wave will peak. Naturally, it’s something most people want to know, but in retrospect I think it’s the wrong question. Instead, we should ask how we can minimise the impact of the current and future waves. The omicron wave won’t be the last. Why would it be? Look at the UK: the first wave of the original strain was followed by the alpha variant, then the delta variant, omicron BA.1, and now omicron BA.2. An average of ~100 people continue to die per day.
Mar 9 5 tweets 2 min read
Younger kids now have to wear masks in Perth. How are they coping?

👧 “Really excited, ‘cause I quite like wearing a mask.”

🧒 “I’m kind of fine with it, but the mask is kind of sweaty on the inside.”

If this is the worst TV could find, I’d say most kids are doing just fine. Most of the concern around children and masks is unfounded. If you explain why masks are needed in age-appropriate language, most kids will want to do the right thing and protect themselves and others.

Kids have a strong sense of fairness that many adults have sadly lost.
Mar 9 7 tweets 2 min read
A new study supported by the CDC shows that in 2021, there was more COVID-19 in US schools than the general community (see lines on the left).

But when masks were introduced at school, cases in schools plummeted (see lines on the right).
cdc.gov/mmwr/volumes/7… Both students and staff members were more likely to have COVID-19 than the general community, as shown in this graph (depicting the ratio of school to community cases).

The closer the curves are to 1 on the horizontal axis, the closer schools matched the general community.
Mar 3 9 tweets 3 min read
Today, Western Australia ended the border controls that have kept its people safe for two years. During that time, only 10 people died from COVID-19, making the state’s response one of the world’s best. Unfortunately, the emergence of the omicron variant finally made Western Australia’s elimination strategy unviable.

Nonetheless, the Government continues to follow a suppression strategy for now. Better vaccines may make this easier in future.
Feb 13 10 tweets 4 min read
Is the pandemic really over? What’s likely to happen over the next 12-18 months? The UK’s Scientific Advisory Group for Emergencies (SAGE) outline four possible scenarios ranging from optimistic to pessimistic.

Here’s what they describe…🧵
gov.uk/government/pub… In the best case scenario, the vaccines retain their effectiveness against new variants (which do not show increased transmissibility or severity). Antiviral drugs stop people from getting really sick and these drugs remain effective. Only minor seasonal/regional outbreaks occur.
Feb 7 4 tweets 2 min read
COVID-19 can cause lasting damage to the cardiovascular system, even in “mild” cases that didn’t require hospitalisation during the acute phase of infection.

A new study shows we’re going to see more heart disease, strokes, blood clots & other problems.🧵
nature.com/articles/s4159… The authors have a warning for governments letting the virus spread:

“Governments and health systems around the world should be prepared to deal with the likely significant contribution of the COVID-19 pandemic to a rise in the burden of cardiovascular diseases.” (Continued 👇.)
Feb 5 5 tweets 2 min read
I suspect a single-dose booster won’t be enough against the omicron strain, because it’s changed so much it’s almost like a new virus. One dose wasn’t enough against the original strain, either. Two doses seems more realistic. Our best bet for bringing the pandemic to a end may be nasal spray vaccines.

Early experiments suggest these may be more resistant to variants and do a much better job of preventing infection and blocking transmission than the current generation of vaccines.
Jan 25 5 tweets 3 min read
Western Australian schools will get CO2 monitors and a HEPA air cleaner in every classroom as part of a world-leading reopening plan.

High school students will need to wear masks, as will primary school students if cases rise. 😷
amp.abc.net.au/article/100779… If a child tests positive, they and their family will need to isolate, as will all of their classmates.

This is a sensible policy that will prevent widespread transmission in the community and therefore help to keep schools open in the long-run.
Jan 1 6 tweets 2 min read
Concerning new UK data show protection against hospitalisation is greatly reduced for the omicron variant. About 6 months after 2 doses, effectiveness is reduced to 52%.

Note this is a combined analysis of all vaccines - some may be higher, some lower.
assets.publishing.service.gov.uk/government/upl… The good news is that a third vaccine dose brings protection against hospitalisation up to 88% for the omicron variant.

Protection against hospitalisation caused by the delta variant remains at a very high level, for both two and three doses.
Dec 30, 2021 6 tweets 2 min read
The omicron variant is NOT mild.

Hospitalisations are 40-45% less likely than with the delta variant (imperial.ac.uk/mrc-global-inf…), but the delta variant is >2x more severe than the original strain (cmaj.ca/content/193/42…).

The omicron variant is AT LEAST as bad as the 2020 virus. But the omicron variant is far more transmissible, and our vaccines don’t work as well against it.

This means that an omicron variant epidemic will infect far more people than a delta variant epidemic would.
Dec 20, 2021 4 tweets 2 min read
I recently went to two Christmas parties. Not a single person was wearing a mask.

And it was okay, because there’s no epidemic where I live. Western Australia has managed to sustain zero COVID for nearly 2 years.

Eliminating COVID-19 was always possible. The world chose not to. This got people talking. Good. But the point isn’t Christmas parties or Western Australia. It’s that elimination is the only long-term strategy for ending the pandemic. I’m not someone who typically praises China, but the government there understood this.
Dec 8, 2021 10 tweets 4 min read
I won’t sugar-coat things. This is a disaster.

People vaccinated with 2 doses of the Pfizer-BNT vaccine likely have no protection against infection with the omicron strain. Protection after 3 doses has likely taken a big hit as well.

What it means for severe disease is unclear. There are similar data from South Africa.

Antibodies collected from people vaccinated with 2 doses of the Pfizer-BNT vaccine fare poorly against the omicron variant, although vaccinated people with a previous infection fared better.

But getting infected still isn’t a good idea! Image
Nov 18, 2021 4 tweets 2 min read
A study analysing the health records of people with COVID-19 has found that those who were taking SSRI antidepressants were less likely to die from the virus.

There was an 8% reduction for any SSRI, 28% for fluoxetine, & 26% for fluoxetine or fluvoxamine.
jamanetwork.com/journals/jaman… Image The researchers tried to match people taking antidepressants with a group of control patients, based on age, sex, ethnicity, and medical history.

However, this wasn’t a randomised controlled trial, and it’s possible that other unmeasured factors affected the results.
Oct 24, 2021 4 tweets 2 min read
The AY.33 sub-lineage of the delta variant might not be readily detectable with current PCR or rapid antigen tests. These can be updated, but in the interim, cases may go undetected.

This is one reason why Australia’s plan to end hotel or home quarantine is premature. This isn’t the first time variants have caused testing issues. One of the reasons the alpha variant was noticed was because tests for the spike gene returned false negatives.

Fortunately, the tests also looked for other parts of the virus, which had not changed significantly.
Oct 23, 2021 4 tweets 2 min read
Do you know what’s really funny? I’ve published more on geriatrics than @DrKGregorevic.

And while *I* have published papers on cognitive impairment and dementia, I can’t find a single paper on that subject by Dr Gregorevic in PubMed. For example, not long ago, I published:

Incidence and predictors of cognitive impairment and dementia in Aboriginal Australians: A follow-up study of 5 years

And one of the projects I’m currently working on is a cluster RCT to improve dementia detection.
Oct 18, 2021 14 tweets 3 min read
Long COVID is real, and we need to protect children from it. In Israel, long COVID clinics for children are busy. The clinic at the Schneider Children’s Medical Center in Petah Tikva has about 150 patients and hundreds more are waiting for treatment. 🧵
haaretz.com/israel-news/th… Liat Ashkenazi-Hoffnung, a clinic doctor says that in some children long COVID "appears as a direct continuation of severe illness but in very many of the children, there is a severe illness, followed by a lull of several months and only then do the symptoms of long COVID begin."
Oct 14, 2021 4 tweets 2 min read
A new study of weekly testing of children and staff at a Belgian primary school shows what we’ve always suspected: if mitigation measures aren’t in place, transmission is common between children and adults at school, and it spills over into households.
jamanetwork.com/journals/jaman… In this study, the researchers found:

✅ adult-to-adult transmission
✅ adult-to-child transmission
✅ child-to-adult transmission
✅ child-to-child transmission
Sep 29, 2021 11 tweets 3 min read
Although there are issues with waning immunity, current COVID-19 vaccines offer excellent protection. But this might not always be the case. Future variant-specific boosters may preferentially boost responses to the original strain and be less effective.🧵
cell.com/trends/immunol… The theory works like this: a person exposed to strain A of the virus (either by vaccination or infection) may prime their immune system such that the ability to make future antibodies specific to a future strain (strain B) is reduced.

This is known as immune imprinting.