# ReadyVax vs Parameter

The clearest difference is in-app purchases: ReadyVax at none against Parameter's 1. ReadyVax also leads on iOS requirement (14.0 vs 17.0). Parameter's advantage is update cadence (every 2 days vs every 25 months). On price, ads and device support there is nothing between them.

Both are free to download. Parameter sells 1 in-app purchase, starting at $1.00 per month. ReadyVax asks for nothing beyond the download.

ReadyVax ships an update every 25 months, Parameter every 2 days. The most recent releases landed on October 1, 2026 and September 22, 2026 respectively.

## The numbers

| Metric | ReadyVax | Parameter |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.4 (7 ratings)](https://appshunter.io/ios/app/readyvax/id957851259/reviews)** | — |
| Number of ratings | **7** | — |
| Positive reviews | 75.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 25 months | **Every 2 days** |
| Monetization | Free | — |
| Size | 19 MB | 20 MB |
| Requires iOS | **14.0** | 17.0 |
| Devices | iPhone, iPod | iPhone, Apple Watch |
| Age rating | 17+ | 4+ |
| Developer | [Emory University](https://appshunter.io/developer/387102326) | [JACOB CLINTON PEWITT YANCEY](https://appshunter.io/developer/6788824121) |

## What reviewers say

### ReadyVax

[App page](https://appshunter.io/ios/app/readyvax/id957851259)

Provides up-to-date, evidence-based information on vaccines and vaccination schedules. Designed for both healthcare professionals and general users, it offers customizable data views and real-time alerts for important updates.

**Highlights:** Up-to-date vaccine recommendations, Vaccine safety profiles, Disease prevention information, Real-time alerts and updates, Customizable data presentation, Offline access to information

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### Parameter

[App page](https://appshunter.io/ios/app/parameter/id6788824119)

**Features:** Apple Watch app, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Parameter Monthly | $1.00 | per month |


## Frequently asked questions

### Is ReadyVax free?

ReadyVax is free to download, with no in-app purchases.

### Is Parameter free?

Parameter is free to download, with in-app purchases available.

### Do ReadyVax or Parameter have ads?

Neither ReadyVax nor Parameter shows ads.

### Which is updated more often, ReadyVax or Parameter?

ReadyVax ships an update every 25 months, and Parameter every 2 days. Most recently, ReadyVax was updated on October 1, 2026 and Parameter on September 22, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*