When it rains, it pours - what does it mean in this context?

[GoodTaste]

The idiom "When it rains, it pours" usually means that when things go wrong, a lot of things go wrong at the same time. But in this context, things about vaccines appear going well ("researchers say the data look good enough to merit testing the vaccines"). So the idiom seems to mean differently here.

What does it mean then?
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When it rains, it pours. In the past few days, scientists working at feverish pace to develop vaccines against the coronavirus have released a flood of data from their first human trials.

The results come from phase I and II trials of four promising vaccine candidates and detail how people respond to the jabs. Because the trials were focused on safety and dosing, the data cannot say whether the vaccines will prevent disease or infection — large-scale efficacy trials are needed for this. But they suggest that the candidate vaccines are broadly safe, and offer the first hints that vaccines can summon an immune response that resembles that of people who have been infected with the virus. Crucially, researchers say the data look good enough to merit testing the vaccines in efficacy trials, in which volunteers receive a vaccine or placebo and rates of COVID-19 disease are compared between groups.

Source: Nature 21 JULY 2020
Coronavirus vaccines leap through safety trials — but which will work is anybody’s guess
https://www.nature.com/articles/d41586-020-02174-y

 

[tedmc]

The idiom applies to both good and bad things, more commonly used in the negative sense.

https://idioms.thefreedictionary.com/when+it+rains,+it+pours

 

[GoesStation]

The phrase has been the slogan for an American brand of salt for over a hundred years. The company would not have adopted it if it had a negative connotation.

 

[SoothingDave]

It's also quite clever. It's meant literally, as well as referencing the expression.

The company's logo and its motto, "When it rains, it pours", both originating in a 1914 advertising campaign, were developed to illustrate the point that Morton Salt was free flowing even in rainy weather. The company began adding magnesium carbonate as an absorbing agent to its table salt in 1911 to ensure that it poured freely. However, around 1958, the company realized that their salt was not living up to their slogan. A chemist, Richard A. Patton, was given the assignment to solve this problem. He invented a machine that would coat the salt with a byproduct of salt mining, magnesium oxide. Calcium silicate is now used instead for the same purpose.[SUP][3][/SUP]

 

[Charlie Bernstein]

A similar expression: Feast or famine.

- Last year no one wanted to go out with me, but now it seems like everyone does. Feast or famine!

 

[GoesStation]

A similar expression: Feast or famine.

- Last year no one wanted to go out with me, but now it seems like everyone does. Feast or famine!

That one is pretty much only used positively.

 

[GoesStation]

The phrase has been the slogan for an American brand of salt for over a hundred years. The company would not have adopted it if it had a negative connotation.

Notwithstanding the above, you'll usually hear "When it rains, it pours" said about something inconvenient, such as when an office suddenly gets swamped with work. The alternate version "It never rains but it pours" means exactly the same thing.